The Morality of Quantum Computing - <AUTHOR> https://www.scottaaronson.com/blog/?p=4405 <comment><USER2> Personally I find it really irritating that so many people, such as the humanities teacher, suggest that technology has made life on Earth worse recently like it's a commonly-understood truth. Yes there are problems with a handful of companies right now, but for the most part life has been improved for the vast majority of people in the world thanks to things like mobile phones.

<comment><USER3> I don't think the concern here is the abuses of companies, or technologies like mobile phones. The concern is technologies like thermonuclear weapons (much worse than even nuclear weapons used against Japan), which we are just very lucky have so far not been used in earnest. I think it is a commonly- understood truth that those technologies present an existential threat to society, if not all humanity.

Artificial intelligence is assumed by many to present such a threat (i.e. Terminator-style intelligence singularity scenario). Many speculate that applications enabled by quantum computing could also be similarly dangerous.

<comment><USER4> There is also an argument that nuclear weapons were actually a greatest good for humanity, as they prevented wars between countries that have them.

</comment></comment></comment><comment><USER5> "Today, of Americans officially designated as "poor," 99 per cent have electricity, running water, flush toilets, and a refrigerator; 95 per cent have a television, 88 per cent a telephone, 71 per cent a car and 70 per cent air conditioning. Cornelius Vanderbilt had none of these." \--Matt Ridley in "The Rational Optimist: How Prosperity Evolves"

<comment><USER6> I don't like this trope because it obscures the one thing that wealthy people know and non-wealthy people don't.

Money is time. It's not gadgets or electricity or running water or toilets. It's time for yourself, your family, your religion (if you have one), and whatever hobbies make you tick. If you're on the hook to do someone else's bidding for 8+ hours a day, you are not wealthy, no matter how much they're paying you.

Today's poor are worse-off than those in times past regardless of whatever trinkets they have. In almost every culture and occupation throughout history up to the industrial revolution, working people have never spent 8+ hours a day, year round, in servile labor. It's absurd.

Regardless of how many Scooby Snacks you're so generously awarded by today's silicon robber barons, you will be poor until you stop measuring your life in trinkets and start measuring it in time.

<comment><USER7> I'm not sure I buy that. Would you consider doctors significantly poorer than most other professions? Or surgeons at the least.

<comment><USER6> Doctors are a rare breed. Now that the money isn't what it used to be (for most specialties, and in proportion to the cost of education), very few go into it as a "lifestyle profession". It attracts only the workaholics. Same with law.

<comment><USER8> Hopefully, the word you're looking for is "vocation".

</comment></comment></comment></comment></comment><comment><USER9> > A quantum computer is not like a nuclear weapon: it's not going to directly > kill anybody

This is, of course, not the only problem with nuclear weapons (and by extension the science and technology that created them). First, there are several _indirect_ ways that a single nuclear detonation could kill people. Second, the realization of nuclear weapons create a world in which nuclear war is possible -- one where mass detonations could alter the planet so radically that there would be innumerable _indirect_ threats to everyone. Third, consider the way that the amassing of nuclear weapons so altered the geopolitical landscape, and what the effects were.

This is precisely what the letter-writer is hinting at -- that we should be competent enough to strongly consider possible unintended consequences. Despite the prominent stream of thought on this site, no particular technology is in itself "inevitable." We have the capability, collectively, to choose whether or not to pursue something.

<comment><USER10> > We have the capability, collectively, to choose whether or not to pursue > something.

This is the coordination problem to end all coordination problems.

Is there an example in history of civilization turning its collective back on some scientific pursuit in fear of its potentially negative consequences? It seems close to impossible. There are too many different value structures out there, and there's too much money on offer to anyone who can give any government or large corporation an advantage over its competitors.

You may be able to convince a few researchers today, but as soon as China has the slightest breakthrough towards X or Y technology, most of those who signed the pledge will be tripping over themselves to get cracking on the problem.

<comment><USER9> > Is there an example in history of civilization turning its collective back > on some scientific pursuit in fear of its potentially negative consequences? > It seems close to impossible.

First we should ask: is this a "scientific" pursuit in the first place? Or, rather, are we describing the creation of some mechanisms (based themselves on scientific discovery) that can be used for all kinds of purposes, among them, yes, future scientific practice? Computing leverages scientific discovery, and aids in its practice, but is itself not science.

Second, and at the risk of sounding trite, we can also ask "is there an example in the history of civilization of someone flying before the Wright brothers?" or "is there an example in the history of civilization of a world governing body before the 20th century?" The very promise of democracy, in general terms, is that we should, in fact, be able to make large decisions together on a society-wide scale. And because that is, ostensibly, the highest level through which we coordinate, we can should also be able to direct how our democratic institutions help us achieve those aims. If your position is that money, corporate influence, or government corruption prevent such coordination, you are certainly correct. But these are not "natural law." We have the ability -- however likely -- to deal with those problems. Otherwise, what's the point?

> You may be able to convince a few researchers today, but as soon as China > has the slightest breakthrough towards X or Y technology, most of those who > signed the pledge will be tripping over themselves to get cracking on the > problem.

We are not limited to pledges. But even in that case, it is then up to those scientists who turn a dime to deal with their own potential moral failings.

</comment></comment></comment><comment><USER11> In my opinion Scott was really generous even answering. Horan makes no attempt at supporting his claim that QC will move us closer to midnight on the Doomsday Clock.

<comment><USER12> Horan is not claiming those things. Horan is wondering if the experts have considered those things. Scott's hand waving answer suggests that "no the experts have not." Engineering professionalism entails formal assessment of the risks. The burden of proof is on the engineer. Without that, it's astrology not engineering.

<comment><USER11> Quoting Horan:

 _But how close does the hand on that doomsday clock move to midnight once we "can harness an exponential number of amplitudes for computation "?_

Looks like a claim to me.

<comment><USER13> but it ends with a question mark?

<comment><USER11> Implicit in the question.

<comment><USER13> Yeah, you're right.

</comment></comment></comment></comment></comment></comment><comment><USER14> Technology is mostly neutral morally*

It's good in the hands of ethical people. It's bad in the hands of unethical people.

Nothing about quantum computing changes this fundamental premise.

I would say that the scale of good or bad that can from using quantum computing is much higher than other upcoming technologies. But beyond that, nothing is particularly different than any other new technology in this regard.

*When I say technology here I am referring to over-arching technologies not specific applications. E.G. Nuclear technology in general, not nuclear power or nuclear weapons specifically.

</comment><comment><USER15> I think you could ask this about all of science and invention - it is hard to know what the outcomes will be with any new knowledge.

<comment><USER16> [http://dresdencodak.com/2009/09/22/caveman-science- fiction/](http://dresdencodak.com/2009/09/22/caveman-science-fiction/)

</comment></comment><comment><USER17> Technology is not morally neutral, it is always immediately good (as a new tool that extends our agency) but can be of course used to cause greater evil. Quantum supremacy is one of the greatest things humanity will have ever achieved, right there with the scientific revolution and abolishing the institution of infanticide.

</comment><comment><USER18> > But in any case, there's already a push to switch to new cryptographic codes > that already exist and that we think are quantum-resistant.

Hopefully this will happen soon. I don't know of any quantum-resistant ciphers though.

<comment><USER19> > I don't know of any quantum-resistant ciphers though.

Almost all widely used symmetric cryptography is more or less quantum resistant already.

Hash based signatures are the obvious quantum resistant signature, except where their size precludes them-- ( [https://sphincs.org/](https://sphincs.org/) for a good example).

For key agreement and asymmetric encryption the story is more complicated. Classical error correcting code based cryptography has a lot of reasons to feel positive about it security, but the public keys are large enough to make them inapplicable to many applications. ( [https://classic.mceliece.org/](https://classic.mceliece.org/) for a good example )

For communications efficient key agreement or various zero-knowledge proofs other than signatures the field is much more complicated and the trade-offs less clear. There are a bunch of candidates in the NIST PQ contest, from several different distinct classes of hard problem. ( [https://csrc.nist.gov/Projects/Post-Quantum- Cryptography](https://csrc.nist.gov/Projects/Post-Quantum-Cryptography) )

</comment></comment><comment><USER20> Can we estimate how much energy would a server farm of quantum computers (capable of doing something useful) need?

<comment><USER21> Yes, but it would be kind of like Charles Babbage estimating how much coal would have to be burnt to power the Analytical Engine.

<comment><USER20> Well, if it's going to take 150 years to get to that point, maybe they should stop with the hype already.

</comment></comment></comment><comment><USER22> > _But in any case, there's already a push to switch to new cryptographic > codes that already exist and that we think are quantum-resistant. An actual > scalable QC on the horizon would of course massively accelerate that push._

Wikipedia has a good review on major subdivisions of Post-Quantum Cryptography.

* [https://en.wikipedia.org/wiki/Post-quantum_cryptography](https://en.wikipedia.org/wiki/Post-quantum_cryptography)

In short, in additional to integer factorization and (elliptic) discrete logarithm, there are a lot of others hard problems that can be used to construct public key encryption algorithms.

* Lattice-based cryptography

A "lattice" is a mathematical structure in abstract algebra. The study of it originally came from the theoretical analysis in solid-state physics on the structure of crystals, and can be understood as a matrix of evenly spaced "dots" in space. Formally, it's a discrete subgroup of an addictive group in an n-dimensional space.

            *   *   *   *
           *   *   *   *
          *   *   *   *
         *   *   *   *

        (This is a lattice)

There exists several problems about them that are believed to be extremely difficult, called Lattice Problems. One well-known example is the Shortest Vector Problem: given a lattice _L_ in vector space _V_ and a norm _N_ , find the shortest non-zero vector in _V_ , measured by _N_ , in _L_.

There are fast approximate solutions, but under certain circumstances, this is an NP-hard problem, so we assume that we can construct a system, that is difficult to solve, although it's not HP-hard.

NTRU is an algorithm that utilized a similar problem about lattice, proposed in 1997, no fundamental problems have been found in the original algorithm, so even after 20 years, it remains unbroken today.

OpenSSH contains an implementation that you can use now today.

But it requires LARGE (many KiB) public key - there's a large system of polynomials. Also, parameter selection is a question.

* Learning With Errors (LWE)

In theoretical machine learning, there's a problem called "Learning with Errors". I don't understand this problem well, but basically, we have a system of linear polynomial equations, but with random "noise". Solving this system of equations is believed to be extremely difficult.

And interestingly, Oded Regev proved this problem is as difficult as some of the worst Lattice Problems. So LWE is considered a branch of Lattice-based Cryptography. There is also a variant of this problem, called Ring-RWE, which is more efficient for cryptography.

Example includes Google's NewHope ciphersuits.

Again, LARGE pubkey.

* Multivariate cryptography

Solving a system of polynomial equations with many variables in a finite field F,

        y1 = G1(x1, x2, x3)
        y2 = G2(x1, x2, x3)
        y3 = G3(x1, x2, x3)
        ...
        (G is a polynomial equation)

is believed to be a difficult problem, and is NP-hard and NP-complete for a random system. And it has been proved that the case of solving a system of 2rd-order polynomial equations (quadratic equations) is already difficult enough, and this question is called the Multivariate Quadratic Problem.

This fact can be used to construct public-key cryptography. However, because the system cannot be random, it's not NP-hard or NP-complete (there is no system that is NP-hard in the entire study of cryptography, otherwise, how do you decrypt it...), but we believe that we can construct a system that is difficult to solve practically.

Unfortunately, attempts on creating public-key encryption algorithms is largely unsuccessful, but there are successful digital signature schemes, such as _Oil and Vinegar_.

Again, LARGE pubkey.

* Hash-based Cryptography

This scheme is proposed by Ralph Merkle in the late 70s, and remains unbroken today.

First, generate 2^n pairs of random public and private keys (X, Y), and hash all private keys, let's say we have 4 keypairs. Placing these hash values Y0, Y1, Y2, Y3 at the bottom of a binary tree as leaves.

We connect and hash the two surrounding values to obtain the next layer (think blockchains), so hash (Y0 + Y1), hash (Y2 + Y3), and built the tree recursively until we reach the root.

          H(H(H(Y0) + H(Y1)) + H(H(H(Y2) + H(Y3))) ... 1 node
                   ^           ^
         H(H(Y0)  +  H(Y1))  H(H(Y2)  +  H(Y3))    ... 2 nodes
          ^         ^         ^         ^
         H(Y0)     H(Y1)     H(Y2)     H(Y3)       ... 4 nodes

To sign a message, simply select an unused keypair (X, Y) to create the signature. The signature also contains additional information to show that the (X, Y) can be traced to the root of the Merkle Tree (think Bitcoin Wallet?).

It has been proved that the its security can be reduced to the security of the underlying hash function.

XMSS is such a system, and there is already an RFC standard for it. OpenSSH contains an implementation that you can use now today. The problem is its large keysize and limited number of signatures, and more importantly, it's stateful. Key reuse is FATAL.

DJB has an attempt to make a stateless version, called SPHINCS.

* Code-Based Cryptography

This approach uses the difficulties on decoding error-correction code. Decode a general linear code is NP-hard. First, select a system of code that is easy to decode for us, as the private key, and transform it to a obscured form, as the public key.

A classic algorithm is McEliece, it's known since the late 70s, as old as the original Diffie-Hellman, and still remains unbroken today, but it uses binary Goppa codes which requires LARGE keys.

* Supersingular Elliptic Curve Isogeny cryptography

The math is even beyond description to a layman like me. Basically, "isogeny" is a mathematical structure in abstract algebra, and we can find a bunch of supersingular elliptic curve in the same isogeny, and use the property of this isogeny to encrypt data. Just like the ordinary elliptic curve cryptography, which we use a bunch of points on the same curve and use the property of this group to encrypt data.

An example of such algorithm is SIDH, and it's a new candidate for post- quantum Diffie-Hellman exchange, but requires a lot more CPU time.

</comment><comment><USER23> Writing is a technology.

</comment><comment><USER24> I'm no fan of Trump, but the false moral equivalence parenthetically made of Trump to Xi Jinping who jails journalists for even expressing a semblance of dissent on social media tells you all you need to know about what Scott's opinion on morality is worth.

<comment><USER25> I read that as The Americans, The Russians, or The Chinese with their current leaders written in as stand-ins.

<comment><USER26> The false moral equivalence of american government with the totalitarian dictatorships of China and Russia is extremely misguided.

<comment><USER27> Domestically, yes. Internationally, no. The US has a long history, comparable to if not more extensive than either China or Russia, of supporting totalitarian regimes in other countries.

When accessing the potential danger of a new technology, for a large number of ordinary people in a lot of places around the world the chances of it being misused by the US against them is as likely as it being misused by Russia or China against them, and so lumping those three together is not unreasonable.

<comment><USER24> China is quite literally imprisoning their own citizens based on their faith and harvesting their organs for buyers while they are still alive. That's in addition to their Orwellian social credit system. That's in addition to their less recent massacres and abuses of totalitarian power. Please just stop. There is literally no comparison. If you asked me to die by a gas chamber or by being paralyzed, but still aware, and have my kidneys taken out, I'd take the gas chamber.

</comment></comment></comment></comment></comment><comment><USER28> > _The morality of that, of course, could strongly depend on whether the > codebreakers are working for the "good guys" (like the Allies during WWII) > or the "bad guys" (like, perhaps, Trump or Vladimir Putin or Xi Jinping)._

Yeah, not so sure about that. The allies might have been the "good guys" in WWII, but before and after they have enslaved 1/3rd of humanity as subjects in their colonials empires.

And they have been busy making enemies, toppling governments, meddling, dividing and conquering, etc all around the globe before and after WWII, and during the Cold War.

So, yeah, unless we compare to bona-fide Nazis, color me unimpressed with the idea that some group is so much better to unlock QC...

Besides, wasn't Germany itself, with tons of ex-Nazi leaders, sympathizers, and supporters in all areas of post war leadership [1], best pals with said Allies a mere few years after the war? (as West Germany was a good asset to have for Cold War purposes (and East Germany for USSR for the same)

Let's say the good and bad guys are in superimposition, as finger-pointing the fashionable names to be against in US politics du jour (Trump, Putin, Xi) doesn't really inspire confidence...

[1] So much that a big demand of younger germans in the 60s and 70s was the "denazification" of the country (I'm not speaking here of the namesake half- hearted allied attempt).

</comment><comment><USER29> Nice take. It feels like the underlying question is "what should humans make a priority?". But we lack hindsight: it's a multi-armed bandit problem[0].

So the strategy should be in this case: let's try, and move towards what benefit us the most, and run away progressively from those things that aren't doing so.

Of course, how do we define "benefit" is the tricky part that's left to the reader...

[0] [https://en.wikipedia.org/wiki/Multi- armed_bandit](https://en.wikipedia.org/wiki/Multi-armed_bandit)

</comment><comment><USER30> Article Preview:

This morning a humanities teacher named Richard Horan, having read my NYT op- ed on quantum supremacy, emailed me the following question about it:

```

Is this pursuit [of scalable quantum computation] just an arms race? A race to see who can achieve it first? To what end? Will this achievement yield advances in medical science and human quality of life, or will it threaten us even more than we are threatened presently by our technologies? You seem rather sanguine about its possible development and uses. But how close does the hand on that doomsday clock move to midnight once we "can harness an exponential number of amplitudes for computation"?

```

I thought this question might possibly be of some broader interest, so here's my response (with some light edits).

Dear Richard,

A radio interviewer asked me a similar question a couple weeks ago—whether there's an ethical dimension to quantum computing research. I replied that there's an ethical dimension to everything that humans do.</comment>


Show HN: Try Riding the Boosted Board for Free in SF - <AUTHOR> http://tryboostedboards.com

<comment><AUTHOR> I absolutely love riding the Boosted Board. It's an amazing vehicle that goes up to 20MPH and weighs just 15lb. I plan on solely using my Boosted Board to commute around SF.

I'm happy to answer any questions or concerns about this service.</comment>


First-run experience on the mobile web - <AUTHOR> https://twitter.com/lukew/status/1167532821608484864 <comment><USER2> To some degree, this is an 'acceptable' experience for a Desktop/Laptop user to have these notices present on the web which some may tolerate this. But still in 2019, this has continued to be worse on mobile, and they have brought the mobile web experience into the dark-ages of the 2000s.

Usually the phrase 'the modern web' doesn't fit well in this regard for mobile web users and reducing the web page real-estate with notices, ads and paywalls drives users off completely.

It is no wonder that they use an app instead and also makes the case for PWAs too.</comment>


General factor of intelligence g, a Statistical Myth - <AUTHOR> http://cscs.umich.edu/~crshalizi/weblog/523.html <comment><USER2> It's a great article. But it's a bit more philosophical than practical, and I particularly take issue with the author's use of the term "statistical myth".

Near as I can tell, Thompson's model is the following: there are lots of abilities, and any test uses many (232+) of them at random. Individuals have a random selection of abilities.The author then declares that any individual ability is not g, since no specific ability describes performance very well. All very true.

But there is a single, explanatory variable in this model: g = # of abilities an individual has [1]! Moreover, Thompson's model makes a specific prediction about g - it should be normally distributed. So overall, I agree with the author's scientific argument: g is very likely to be decomposable into subfactors.

But I don't agree with his claim that g is a "statistical myth". Let me give an argument illustrating the fallacy he is making. Suppose I want to explain the thermodynamic law PV=nT. I can build a moderately more complicated statistical model [2] involving only 10^23 newtonian particles, with normally distributed velocities, and completely reproduce all the predictions of the thermodynamics. But not a single one of those particle positions explains pressure or temperature! Thus, thermodynamics is just a statistical myth.

Thermodynamics and g are simplified models of the world, based on the fact that the macroscale is dependent primarily on the sum of a large number of microscale variables [1]. They both have decent, though imperfect, predictive power. There is almost certainly a more complicated underlying theory, which will reproduce thermo/g as theorems about statistical aggregates. (For example, g may eventually be explained as the interaction of neurons.) Does this make them "statistical myths"? Of course not. Just macroscale models which have an underlying microscale explanation.

[1] Or perhaps a weighted average based on how frequently abilities are used in tests.

[2] <http://en.wikipedia.org/wiki/Statistical_mechanics>

[3] For example, pressure is the the average force imparted by particles colliding with the side of a vessel divided by the area on which the collisions occur.

<comment><USER3> Reading the original article further I understand more of what the author meant -- and I agree with him more.

What he means by "statistical myth", I think, is that you can throw any number of measurements into a big bag, even weakly correlated, and you'll always be able to find a general macro-factor that is correlated with all of them and therefore seems to "describe the bag" pretty well... even if the bag itself is absolutely meaningless.

For example, one could throw into the bag height, sexiness, feet length, and BMI, which are all somewhat correlated with one another and with "IQ".

There is a macro factor describing such a bag; but would you call it "general intelligence"?

 _The fact that we talk about g is because we consider a priori that there actually is such a thing as "general intelligence"_ and that we are measuring elements of it. Maybe we are, maybe we're not; correlations alone tell us nothing about it.

The analogy with physics, be it temperature or pressure or what have you, is in my opinion quite flawed, because in the case of those entities we know that the elementary events / forces are linked by way of causality with the macro factor, and we know that _for reasons other than mere correlation_.

In the case of g, on the contrary, _the only link between the different elements is the correlation itself_. And it gets worse: to be included as a relevant IQ test, a new test has to be correlated with g. To quote from the article:

" _By this point, I'd guess it's impossible for something to become accepted as an "intelligence test" if it doesn't correlate well with the Weschler and its kin, no matter how much intelligence, in the ordinary sense, it requires. (...) This is circular and self-confirming, and the real surprise is that it doesn't work better._ "

So g is at the same time what we're looking for and what we're building upon, having decided it's there already.

This looks much more like religion than science.

<comment><USER2> _For example, one could throw into the bag height, sexiness, feet length, and BMI, which are all somewhat correlated with one another and with "IQ"._

The point is that if those phenomena are all correlated with one another, there is likely to be an underlying reason for that. Maybe it's not general intelligence, but there is something.

Suppose you threw a different set of things into the bag: phase of the moon at birth, whether you were bitten by a wolf, and how good you are with computers. These things almost certainly will not be correlated, because there is indeed no relationship between them. The only reason the author discovered a large principal component in all his models is because he explicitly built one in!

Now, my analogy with physics is not to the physics of today. Rather, it's to physics pre-Boltzman. Before that, we didn't really know how the atomic theory of physics was related to thermodynamics. All we really had were correlations - boiling is correlated with burning, with faster chemical reactions, expansion of solids, with the human perception of warmth, etc. We observed they all occurred together, and postulated an underlying variable T which correlated well with all of them. We then exploited the correlation between this hidden variable T and thermal expansion to design a specific test to measure it (thermometers).

Pre-Boltzman, all we had were correlations between fundamentally different physical phenomena. We had various incorrect theories about why some of them occurred together, but that's about it.

Now suppose Boltzman comes along. He says "what you call a single variable T, I can explain with the sum of many variables." Does that mean it's reasonable to conclude T is a "statistical myth"?

<comment><USER4> See, the article is not arguing that. The article has nothing against latent variable(s) to account for what we observe as intelligence. What it is against is, misapplication of methodology. The myth is not in a latent variable summarizing intelligence, that may very well exists as admitted by the author. The myth is that g is derived in a meaningful way and explains the correlations in data instead of being a by product of the fact that the data is made to correlate (these days) and is just a measure of the correlation of the tests (now made to correlate). Again, I remain sceptical you read the article in full.

g is not as useful as T, since its ability as an explanatory variable and verification in experimental settings are sorely lacking.

Also, even if a valid concept of a single explanatory variable for intelligence were created, I personally, remain sceptical of the scope of its usefulness considering the space of complexity at hand (humans, genes, environment,...) and likely a lot less profound and far reaching as the insights of Boltzmann. And on the political side, the capacity for damage it would entail could be large - many people's lives could be impacted negatively. So it would have to be wielded carefully, one eugenics movement is enough.

<comment><USER2> _What it is against is, misapplication of methodology._

Yes, and the author rightly points out that latent variables do not exclude the possibility of microstructure. That doesn't mean the use of the latent variables is a "statistical myth", unless you define the term "statistical myth" so broadly as to include temperature and pressure.

 _g is not as useful as T, since its ability as an explanatory variable and verification in experimental settings are sorely lacking._

This is both undisputed, and unrelated to the author's argument. The difference between our pre-Boltzman understanding of T and our contemporary understanding of g is one of precision. The author's argument was independent of precision, so invoking precision to protect his argument is disingenuous.

You might want to criticize the confidence levels of g. That's a perfectly legitimate thing to do. But that's not what I'm responding to.

 _So it would have to be wielded carefully, one eugenics movement is enough._

Not sure about that. The Dor Yesherim organization does such a great job of eugenics, I'd love to see further eugenics movements in other genetically isolated groups.

</comment></comment></comment></comment></comment><comment><USER5> I wish there were more Cosma Shalizis in the world. Somehow, statistics has become the ultimate in cargo cult mathematics. We need more statisticians who can write clearly to set fire to our thatched airplanes.

<comment><USER6> Pardon my naivety, but what do you mean by "thatched airplanes"?

<comment><USER7> See: <http://en.wikipedia.org/wiki/Cargo_cult>

"Thatched airplanes" being an imitation of the real thing.

</comment></comment></comment><comment><USER8> Even if we can't measure it, what makes it so hard to believe that intelligence is inheritable? Is height inheritable? Yes. Is eye color inheritable? Yes. Is skin color inheritable? Yes. Is physical strength....? Yes. Why wouldn't a human characteristic that has provided one of the biggest advantages through evolution not be inheritable too?

<comment><USER9> The example of the German monozygotic twins Otto and Ewald, both well nourished but sportsmen who pursued different sports, show that physique is exquisitely sensitive to environmental influences even between two individuals who share a genome and a prenatal environment in the same mother's womb. Take a look at the photos.

<http://www.marksdailyapple.com/control-gene-expression/>

[http://www.joebower.org/2010/05/we-inherit-and-we-also- becom...](http://www.joebower.org/2010/05/we-inherit-and-we-also-become.html)

AFTER EDIT: I'm asked in a reply below what my point was, and it's partly to point out that the term "heritable" means something far, far different from "determined by genes." There are whole books

[http://www.amazon.com/Nature-Nurture-Environmental- Influence...](http://www.amazon.com/Nature-Nurture-Environmental-Influences- Development/dp/0805843876)

[http://www.amazon.com/Genes-Behavior-Nature-Nurture- Interpla...](http://www.amazon.com/Genes-Behavior-Nature-Nurture-Interplay- Explained/dp/1405110619/)

[http://www.amazon.com/Dependent-Gene-Fallacy-Nature- Nurture/...](http://www.amazon.com/Dependent-Gene-Fallacy-Nature- Nurture/dp/0805072802/)

by professional geneticists, medical doctors, and psychologists patiently refuting the confusion in most popular literature about what "heritability" means, but the main point in this thread is that Shalizi is correct, and many psychologists are wrong, about what heritability figures mean in relation to IQ.

<comment><USER10> Not really sure what your point is there. It's natural two people with virtually identical genes subjected to vastly different training would have different body-types. It's also natural that two people with vastly different genes would respond differently to virtually identical training.

Consider someone like this boy vs his classmates: [http://www.sciencentral.com/articles/view.php3?type=article&...](http://www.sciencentral.com/articles/view.php3?type=article&article_id=218392292)

</comment></comment></comment><comment><USER11> Cosma was one of my very favorite professors at CMU

</comment><comment><USER12> There's a point he omitted: In curve fitting, exploratory data analysis, data mining, etc., we are looking for X. We don't know if X exists. But if X does exist, then our methods have a shot at finding X. So, we look. Maybe we find something. We test what we find, and it appears to work as we believe X would. So, we start to believe that X exists and we have found it.

Do like following this 'paradigm'? No! But, when people do follow this paradigm and claim to have found X, then I can't be sure they are wrong!

E.g., maybe there is a statistical model that predicts the stock market. So, do a lot of curve fitting. Find something that appears to predict. Then if there is a predictive model, maybe have found it. Test the model on old data not used in constructing the model and see if it works. If it does, then we start to believe that there is a predictive model and that we have found it or something close enough.

When people do such things, I can't say that they are wrong.

</comment><comment><USER12> Largely I agree with him, and at times I suspected some such. E.g., just testing some software, I generated some 'random' symmetric, positive definite matrices, found the eigenvalues, and noticed that there was a big one and the sizes went down quickly. So, in linear equations, a few variables constructed from the eigenvectors of the largest few eigenvalues, can make a good approximation to all of many variables. So, factor analysis makes a good data compression technique. Can't find fault with that.

That just a few of the largest eigenvalues/vectors can explain all the data well is curious. So really he might have just used R and some Monte Carlo to show us how variance explained increases with number of factors used. I'm surprised he didn't do this.

Much or all of this has long been clear.

But what I didn't like was his drifting off into old goals of the psychologists. I couldn't figure out if he was a psychologist with an ax to grind or what. Instead, he's a statistical physicist. Curious.

The psychologists looking for 'causality' have a goal that is from tough down to impossible. We should have been concluding that. That he got off into arguing about 'causality' seemed a bit silly. I don't know all what silly stuff the psychos are trying to believe, but arguing with silly psychos is a bit silly.

But it remains: Give a test with some mental puzzle problems, and in just a linear way can explain a lot of the data with just one factor. Curious. Maybe somewhat useful. 'Causality'? Likely not if only because we know that there is a biological and neurological basis and have made no connection with that.

Then I didn't like his use of 'factors': He has some factors correlated. No: The usual approach is that, like all the eigenvectors are orthogonal, the factors are all uncorrelated. Maybe the psychos look for some uncorrelated 'factors' trying to get at some of their guesses about causality, but in this case he should have been more clear.

Finally, he wants Gaussian to justify being interested in means, variances, and covariances. Well, in the Gaussian case, sample mean and variance are 'sufficient' statistics. But even without Gaussian, means and covariances remain important, e.g., for the inner products in the Hilbert space of L^2 real random variables.</comment>


Ask HN: How has the Amazon AWS outage affected you? - <AUTHOR> Thanks to the Amazon AWS Outage today, I missed the chance to have a QR code generated by my app displayed in an ad in a major newspaper. My Heroku hosted app (I have several) is still down.  My other app was experiencing a huge traffic (30X usual) right when the outage happened.
Both apps are just fun toys, but it hurts for them to be down at such a critical time.
How has the outage affected you? <comment><USER2> Our database (RDS) is completely inaccessible -- so our website has been down since 2am or so, showing our maintenance page. It's backed up -- but we have no way to download the most recent backup and move to another server. We tried rebooting our db about 11 hours ago -- and it's been stuck in reboot mode ever since. We tried creating a copy from a recent backup -- but it's stuck in boot mode. We can't move the snapshot to the West Coast farm, so we're really pretty blocked until Amazon gets things in order.

A lot of people on the boards suggested Amazon make the automatic backups of RDS available for download for instances like these. Having a backup is great, but not if you can't access them in an emergency.

On the message boards, someone said that they had selected to have RDS automatically keep a copy in multiple availability zones -- and they said that worked for them. I'm not sure however, since a top post on HN is saying that all of the Virginia zones were effected -- so your mileage may vary.

<comment><USER3> "Offsite Backups" - Where Offsite means, not on Amazon's infrastructure. Seriously.

</comment></comment><comment><USER4> Reddit is down, so I got more work done today.

<comment><USER5> I didn't. I was too busy reading blog posts about the downfall of cloud computing.

</comment></comment><comment><USER6> We're temporarily down with no permanent damage. But we have no way to relay that info to our customers because everything, including our users' email addresses, is inaccessible. Big oversight that I will be fixing as soon as we're back up.

It feels absolutely terrible to only be able to assure customers that their data is safe _after_ they write a panicked email asking if their data is gone.

</comment><comment><USER7> I was hosting a client's app on Heroku and they had a big pitch today during which they weren't able to show the site. Really, really horrible timing.

<comment><AUTHOR> Yikes. That's how I feel... Yesterday I explained how my site, although very ugly, could handle all the traffic you could throw at it and more. Today, it can't handle any.

</comment></comment><comment><USER8> Saw the same RDS behavior nostromo saw: was actually truly interesting. After 2 days of arguing with the RDS database I actually spun up a new local storage instance, logged in over the mysql console at a shell (which actually worked, surprisingly enough) and then found out that a single table (this is a Wordpress instance) was hung: I guess the RDS instance couldn't access the disk file for that table (it was MyISAM which I guess isn't in memory?) so any requests for that specific table hung. As it so happens that was the wp_options table, so there was no way to get past that.

So I sat there with mysqldump and exported each table separately, then spun up a new MySQL instance in another AZ and then imported each table piecemeal. I then re-created the wp_options table from another dump (from an early prototype on Linode, actually) and then manually fudged the values till it all worked. That eventually worked for me.

</comment><comment><USER9> How has it affected me? My posting of the Wikipedia page on "Fallacies of Distributed Computing" made it to #2 on HN, and I got a big karma bump; and wasted more time than usual on HN today, discussing this stuff.

Also, since Quora was down, I didn't get my usual quota of Quora surfing in.

Otherwise, today has been "business as usual." :-)

</comment><comment><USER10> No effect at all that I've noticed. Tarsnap doesn't use EBS.

</comment><comment><USER11> My hastily thrown together article on how to work around EC2 outages got to #8 on HN and received ~2000 reads

<http://news.ycombinator.com/item?id=2471258>

</comment><comment><USER12> I run an app that helps farms manage their weekly or monthly CSA programs. One farm had their monthly distribution yesterday - thankfully they had already downloaded the data they needed to pack and label the orders, but they weren't able to tell customers their final total or send reminders, so they had higher-than-average missed pickups and are receiving money several days later than usual. Farmers are already distrustful of digital/automated solutions, so I'm sad that this has added to that distrust.

</comment><comment><USER13> Startup's site has been down all day, probably lost about ~$500-$1000 in sales, more concerned about the longer term loss of goodwill and the potential damage to google seo rankings though.

</comment><comment><USER14> My leaderboards, user-created levels and other miscellaneous bits of Playtomic run on AWS via MongoHQ and I've spent 1/2 the day answering emails explaining the situation. On the plus side MongoHQ are planning to introduce the ability to mirror databases onto our own servers which is going to be frigging awesome.

It at least highlighted another issue - because users are trying to access databases that don't exist they're taking ages to time out which is bogging down the servers' other thousands of requests/second.

</comment><comment><USER15> Our registration/login/download/stat servers for all our iOS apps (Free Books + Free Audiobooks + Classicly) are all hosted on Heroku, and have been completely down all day. Not good.

</comment><comment><USER16> I am running my phone processing/tracking app on EC2 so it's been up and down all morning. The fall back also has some dependencies on S3 so it has been a bad day.

</comment><comment><USER17> I wasn't able to view a Foursquare checking for a little while and I've had significant amounts of my morning news be related to AWS, the cloud, downtime, etc.

</comment><comment><USER18> My team's single sign on prototype was deployed to heroku so that we could develop our apps against it (Android, iPhone, WP7, jQuery Mobile). It would have stalled development, but with a bit of tweaking I was able to get the prototype deployed to cloudfoundry and everything continued as planned.

</comment><comment><USER19> I manage four EC2s all with EBS and located on the east coast; luckily haven't had any issues.

</comment><comment><USER20> I run my main startup on Heroku, so OrangeSlyce.com has been completely down all day.

<comment><USER21> Might as well get some good out of it.... please describe what your service is.

<comment><USER20> Sadly, I almost replied "just check out the website." I made a site for graphic design students to find freelance gigs that are posted by local small businesses who need cheap, small amounts of design work done. Thankfully this hasn't been very big, and mostly just a side project recently, so not too many users are being affected.

<comment><USER21> That's a great idea, can't wait to check it out when it's back.

</comment></comment></comment></comment><comment><USER22> I've got an app in private beta on Heroku. Closing in on 2 days of downtime.

Not a good way to instill confidence in the 50 or so potential customers I let into the beta.

Plus my iOS app gets data from a Heroku app that is down.

</comment><comment><USER23> My website and e-mail have been down for 12 hours and counting. Alas, my only instance that has survived this is running a website that is still under development.

</comment><comment><USER24> Actually, i was surprised to find i wasn't affected by it at all. Apparently everything i use either knows what they're doing or wasn't in the us-east-1 region.

<comment><USER25> Ditto, we're just in the process of moving to EC2, and were happy to find our staging environment (the only thing moved over so far) is happily healthy (of course it gets minimal load).

</comment></comment><comment><USER26> I provide media streaming services via EC2 to a few customers - basically all of the non-live streams are unavailable.

</comment><comment><USER27> triviatise.com is down, but we just ended our last giveaway to close out our alpha on the 15th so the impact is minimal. We are working to figure out what a good backup plan to heroku is. Im sure a lot of other people (including heroku ) are doing the same.

</comment><comment><USER28> Nope. Our failovers are on self hosted servers, where the core of each app lives anyway.

</comment><comment><USER29> My site still works! (Thanks, prgmr ;))

</comment><comment><USER30> Our test environments aren't available.

</comment><comment><USER31> The company I work for offers a small hosted document management SaaS solution that uses Amazon as the hosted environment, so we've been having issues related to (surprise surprise) EBS.</comment>


Pixel-fitting – how antialiasing can ruin your logos and icons - <AUTHOR> http://dcurt.is/pixel-fitting <comment><USER2> One problem with 'pixel-fitting' is that certain letterforms will appear sharper or crisper than others. For example, in the article the PLUS (from Hulu Plus), the PLU are sharper than the S because more of their outer surfaces conform to square pixels, while the S has continuous curves that have to alias all the way around. So you end up with some characters looking overly crisp while the S looks soft. I prefer to not draw attention to specific characters and have consistent aliasing across all the characters of a logotype. Photoshop has several font rendering modes that let designers choose how aliasing is rendered (Strong, Crisp, etc) to achieve a desirable result, depending on the typeface and font size chosen.

</comment><comment><USER3> This equivalent to TrueType hinting, right? It's funny that hinting went out of fashion over the years, mainly due to a fairly sensible argument from Apple that displays would get better - which they undoubtedly have if you look at an iPad 3. Linux users, who had a choice, started switching from patent- encumbered pixel-fitted full hinting to the softer anti-aliased look, perhaps in part because many of their cool Apple owning friends told them that it "looked right".

So in a way, because of all this history, the pixel-fitted logo actually looks _too sharp_ , and hence a little uncool.

<comment><USER4> This sort of thing is a tough call. I'd say the pixel fitted logo looks better if each is considered in isolation, but viewed as a set the anti-aliased ones look better as they look more consistent.

Fonts have a similar issue. The TrueType font hinting made fonts more readable but sacrificed correct horizontal spacing and often made them less aesthetically pleasing IMO. If I were considering a font purely for on screen work without scaling then I think a carefully designed and hinted font looks best, but if there is going to be any scaling (through different font sizes or zooming in or out) then I'll go with the Apple style every time.

<comment><USER5> I've always felt that the strong hinting used by Windows optimizes for individual glyph legibility by sacrificing kerning and overall readability. I've found that I can't read a whole ebook on a Windows system, but on a Mac I can tolerate it (if I use a large enough font size).

</comment></comment></comment><comment><USER6> This reads exactly like Microsoft's ClearType patent where they shift the 'rendered' glyph around to maximize the number of 'whole pixels' it uses. Sounds like 'pixel fitting' is the same process (albeit done manually it seems).

Waaaay back when I was at USC the Image Processing Institute there here some interesting image filter analysis of high frequency images. Basically when you take a horizontal line, and plot it x/y with X being the horizontal position and Y being the value of the pixel there, you can treat that as a signal and measure the frequency of it. If you look at B&W text you will see a series of very sharp transitions from background level to foreground level and back again. These are square waves which have well defined harmonics. So taking the image and increasing the rate of change between high to low or low to high 'sharpens' it, similarly if you are _rendering_ an image and you have choices about the function which determines which pixel represents which part of the rendered image, you can do several renders with pixel offsets and maximize harmonics for maximum sharpness.

</comment><comment><USER7> I actually find the "sharper" Hulu icon to look _worse_... because the curved parts of the letters stay blurry, while the straight parst are razor-sharp. The "L" and "S" look in the "pixel-fitted" version look totally different, like they don't go together at all.

I don't mind the "extra blurriness" all over everything on my screen at all, because the mind gets used to it quite quickly, and it actually allows for _more_ detail, because our brain automatically interprets sub-pixel width changes, curvatures, etc. This is why fonts on Macs look have more accuracy and detail in their letterforms, because they aren't hinted, i.e. "pixel- fitted".

<comment><USER8> _I don't mind the "extra blurriness" all over everything on my screen at all_

Add that many of us roll at a zoom level != 100%, immediately undoing all of this pixel-perfection work. Only when you're targeting the iOS devices do you have any realistic control over pixel to pixel mapping.

<comment><USER9> And retina has made pixel matching obsolete, the screen resolution is higher than the eye.

</comment></comment></comment><comment><USER10> When using the vector tools in photoshop, it is important to make sure "snap to pixels" is selected. It fixes this issue when creating things like boxes and buttons.

<comment><USER11> In Inkscape I think you have to apply a pixel grid (which can be hidden) and turn on grid snapping.

</comment></comment><comment><USER12> As someone who has been creating digital graphics for broadcast for over 20 years, typically at resolutions that are far lower than anything we have to deal with now, it's interesting to see all this activity lately on HN.

There are times and places where "hand fitting" your pixels is useful, but they are few and far between. Good filtering will almost always get you a better looking result. The constraints on old NTSC monitors are/were horrendous, so you simply _have_ to filter things or you will end up with text and designs that are not only "crunchy" looking, as my assistant used to say, but with images that vibrate, strobe, comb, and burn. Burn like a soul in hell.

The first thing to learn is almost never work with full on black or white. (Or fully saturated color) In broadcast video there are _legal_ reasons for this. But even there, you should always work at least 5% inside your "legal" gamut, or color space. There's plenty of contrast in the remaining space, and it gives you some "headroom" for your filtering to work.

For "white" I like to work down about 15%. The bottom around 10%. This is a starting point, and different designs may make me change things. Anything above or below this should be the result of filtering or as a very, _very_ light application of color, usually feathered and not noticeable. You should be able to "feel" the effect, but not see it.

There's really no getting around the fact that whoever is designing your stuff should know their way around a color wheel. You can use complementary colors to achieve useful contrast. Select your colors to work well together. It's not just a matter of looking "pretty", but a matter of controlling the viewer's eye. It's a form of engineering. And yes, tons of designers don't really get this. The better ones do and are worth the extra money.

Filtering is a matter of making the highly synthetic image you are creating look like something your optical viewing system would find in the real world. All that laborious pixel fitting is simply going to make your image "ring" like a bell if you don't do the other stuff. And if you do the other stuff, correctly, and away from pathological situations, you probably _don't_ need to do the pixel fitting.

If an image is too sharp, it looks fake. Phony. Synthetic. If you are creating a design that is supposed to look like a 15 year old video game graphic, then go for it. (But _those_ were actually pretty blurry and were typically viewed on crummy NTSC monitors.)

So a controlled amount of blur, and I'm not talking about anti-aliasing, can actually help you here. It does help if the image is anti-aliased, but not if the structure of your element is close to the sample size of your image. You shouldn't even be doing that kind of thing. Unless you are creating "small type" that you don't want anyone to read, type should be large enough to filter. If this doesn't fit with your design spec, you've got a design spec done by an amateur.

Now, once you've blurred your image, just a bit, and at the right scale(!), then you can sharpen it a bit. What!?!? But you just blurred it! Yep. Don't go overboard. And don't try it on small details (they probably don't need sharpening anyway. They are small, right?) You can run into trouble on corners, particularly concave ones. Here you _might_ want to do a bit of pixel fiddling, but it should be subtle, and filtered. _Don't_ just go and plunk down a single pixel color change, or a flat color. If you do, that defect will ring like a bell. I used to keep a whole library of photoshop layers with filtery, blurry, corners and edges for dropping into tight spots.

Control your environment. Drop shadows are not a decorative item. Well, they can be, but in this case the thing they do is to create a sense of environment. Soft and fuzzy. Extended, but subtle. You are creating your own fake radiousity space here. And yes, a little creative use of color bleed and fake reflection can work wonders here. But don't overdue it. If the viewer can notice it, explicitly, you've probably overdone it. The window drop shadows on OS X are probably just a touch too strong for my taste. YMMV.

The drop shadow doesn't actually have to be a shadow. It can be though of as merely a filtered edge.

If you really want to get into it, find a good book on oil painting. These tricks have been around for a while. I can recommend the Andrew Loomis classic from the 1930s-40s, _Creative Illustration_. It's full of all kinds of filtering tricks. For a more modern book, James Gurney's _Color and Light_ and _Imaginative Realism_ are both quite good. You can also pick up a copy of one of his Dinotopia books, it won't help designing graphics, but, hey, dinosaurs. Right? (He also has an excellent website: <http://gurneyjourney.blogspot.com/>)

Gradients and ramps are useful, both to break up large flat areas of color and to add depth and a sense of space. But they are also useful on flat, graphic (old sense of the word) designs. A gentle use can place it in the viewer's world space without disrupting the, well, flatness. Just apply the effects uniformly, always being aware of color. Use of these _within_ color fields can be useful and add visual interest and verisimilitude as well. A lighter hand is usually better than screaming "HEY, COLOR GRADIENTS!!!!"

Noise and dithering are also very useful, but can be very dangerous. Less is usually more. Noise is particularly useful on large areas, especially those with gradients. 24 bit color space is actually pretty limited when you start throwing gradients across all your colors.

I grey smallish elements slightly, unless I need them to pop (but you probably _shouldn't_ be needing smallish elements to pop!) Over a uniform or low detail background, a bit of transparency can help, but there are technical limitations here on the web (see below).

When I need the user to look at different areas, instead of "glows" or movement in rollovers, use shifts in saturation instead. High saturation should be used only for directing attention. These days I discourage interactive things like rollovers because, they are a crutch, and mobile devices don't support them. (I have been playing around with using saturation with drag and drop, but it's more for fun and to see what happens. If you try this, be careful.)

Finally, you can use all these effects over the entire visual field. This is more useful inside illustrations or in environments where the content is contained. Vignettes and hot spots, if subtly applied can control the eye, filter the entire scene, and control perceived depth. This is harder in typographic environments, like the main areas of web pages and such. You can use these techniques, but you run the risk of looking less like a web page and more like a "Crazy Eddie" TV ad.

This is all mostly for display areas, illustrations and display type. For the reading typographical areas most of the filtering will need to be done by the OS and you don't have much control over that. You _don't_ want to be screwing around with ham handed filtering on body type. You can _still_ control color and contrast here, but remember old folks eyes, and don't unnecessarily grey the type.

In the new world where we can use Canvas and 8 bit alpha transparency, I've been known to slip in a few vignettes and hot spots as environmental effects. But think of the poor user's CPU, and only do this when it either pays off big time or is in a "display" area like a landing page or interstitial page of some type. Even then, try and talk yourself out of it.

For what it's worth, the hulu logo example in the article looks fine to me. It looks to me like it's been filtered, not just anti-alised. The "improved" one rings, to my eyes. Particularly in the corners.

YMMV.

Edit: Hinting mostly works best with very small elements, like body type, and even then in high contrast situations at high resolutions. Like laser printers. I've always found it annoying on CRTs and flat panels. I used to keep an old pair of reading glasses around to "filter" my screen. These days, with largers monitors, I use a 24 inch, at an appropriate distance, I don't need any filtering than my own aging eyes. The body type looks just great. Younger, sharper eyed readers may not agree, but just wait a few years ...

<comment><USER13> Do you have a blog? I found this really interesting and would like to read more.

Also, I'm curious - what are the legal reasons for not working with full black or white in broadcast video?

<comment><USER14> It's not "legal" as in "a matter of law". It's about the technical specifications of television and how television signals are processed and transmitted. In analog TV the transmission uses AM (Amplitude Modulation). You could create signals that over-modulate the transmitter if not careful. Hence the use of the terms "legal" to refer to signals that would pass through the transmitter without causing any trouble. Most stations would use boxes called "legalizers" to prevent bad signals from reaching the transmitter. However, broadcasters generally have specification documents that content providers must follow in order to submit material that will not be rejected by their QC department.

<comment><USER12> No, it actually was "legal" as in FCC regulations; and you could get fines for broadcasting signal out of spec. (Though I've _never_ known of it happening.)

I'm not sure what the situation is now with digital TV. My last years in the industry were before the mandatory switch, and the places I was working were simulcasting. So we were creating stuff that was NTSC safe. By then most of the software we were using took care of keeping things in spec, but some of the older equipment we were using, mostly character generators and few really cranky old switchers and effects boxes, still required that we be careful about our input levels.

<comment><USER14> OK, you are probably right. It's been a while. I played in broadcast some time ago.

I think you jogged my memory further. I think the way it worked is that the transmitter over-modulation due to illegal levels would/could interfere with adjacent channels and that's why the FCC made the rules.

</comment></comment></comment></comment></comment><comment><USER15> Manual hinting may be fine for simple vector shapes like that, but in most cases it does more harm than good. It's the same debate of windows vs OSX anti-aliasing: windows tries to fit shapes in to the pixels for a sharper look, while OSX favors preserving the exact shapes resulting in more blur.

In the Hulu pixel-fitted example, the typeface is mutilated beyond recognition. Yes, it's sharper, but it doesn't look right, the 'u's even appear higher than the x-height.

In a screen where everything is anti-aliased, images like that stick out like 8-bit art. And just like in HD vs FullHD, most people can't even tell the difference. Be patient and we'll be over this in a couple years :)

<comment><USER16> As a programmer, I switched from Windows 7 to Mac (Lion) since everyone at my new medical-related job uses Macs. I must say that I much prefer the W7 anti- aliasing, because I care little about how close my characters are to their true glyph shapes and care much about how crisp a page of code looks like on my monitor. I've gotten used to the blur now, but whenever I go back and look at my old W7 machine the crisp nature of the text really jumps out at me.

</comment></comment><comment><USER17> I hope I'm not naively over-generalizing a complex process, but is 80% of what he doing just not anti-aliasing straight lines? If that is most of it, couldn't pixel-fitting be improved by just doing that?

<comment><USER18> It's slightly more complicated than that.

For example, in his "Markdown Mark" example, he's careful to make sure that the rectangular border is exactly three pixels wide on every side. Just rounding straight lines to the nearest pixel boundary wouldn't guarantee that (it's pretty easy to wind up with shapes that _should_ look even, but are 2px on one side, and 4px on the other).

TrueType fonts face exactly the same challenges as described in the article, and they include bytecode for a specialised VM to describe how to nudge control points to pixel boundaries. The open-source FreeType rasteriser has code that's pretty good at doing this automatically, but it's very domain- specific to font-rendering; it would be no use to a general SVG renderer, for example.

</comment></comment><comment><USER19> Great post. I would have kudo'd it were I not so annoyed with having been tricked by the kudo button's hover-for-irrevocable-action on another article in the past.

<comment><USER20> I went back to see what you were talking about and now I'm in the same boat as you. I think it's a good opportunity for another cool effect though. I imagine you could hover (after "kudoing") and the animation would happen in reverse resulting in an "un-kudoing".

<comment><USER21> Meh, the effect is trivial and the behavior is bad. The real opportunity is to just fix it.

</comment></comment></comment><comment><USER22> "Until we have Retina displays everywhere, we're going to have to live with antialiasing techniques"

I don't think Apple needs to come in and rescue every display maker in the world with their branding. Any sufficiently high resolution display will do.

<comment><USER23> I agree. Why use the term Retina? That term means nothing to many consumers.

Why not use the company agnostic term HD? You can be even more technical and say displays with 100+ DPI.

<comment><USER24> Perhaps because HD got railroaded by the TV people and now it's commonly taken to mean 1920x1080 rather than a DPI measurement?

Also, your "more technical" definition is off by a long shot; people have been using 100-125 DPI screens for years, that's 100+ and it's not what would pass for a retina display unless it was 40" across and you sat at TV viewing distances away. Retina is being used in the generic sense to say "2X the DPI you're used too", or 250+ DPI for the current examples available. But even that DPI measurement is flexible because it's related to viewing distance.

So rather than stretching for generic terms that dont actually make it any clearer what you're describing, lets just stick with "retina" until we really have a better term :)

<comment><USER23> HD means high definition. The TV people have adopted that term for HDTV, so be it.

I threw a number out there, but should have known better since someone was to nitpick it.

The correct term is PPI (screens) over DPI (printers). Also, PPI is pixels per inch. PPI is not relative to viewing distance. DPI is not relative to viewing distance.[1]

An iPhone 4S has 326 PPI. We already have a technically accurate method to measure pixel density, so let's use it. Use bytes to describe data, not Libraries of Congress.

Retina is a marketing term. Does phone A had better PPI than phone B? I don't know, is Retina better than Super AMOLED++? Why not just compare technical details instead of resulting in fuzzy marketing word arguments?

[1]: DPI does not change with viewing distance, but the closer the viewing distance the higher the DPI needs to be to achieve the same visual effect. A billboard can look the same as a postcard at a much lower DPI because at that distance the human eye can't discern the individual dots.

</comment></comment></comment></comment><comment><USER25> What the author misses is that with colour LCD displays you can do sub-pixel anti-aliasing with the 3 RGB sub-pixels, if you start from a vector, which is why HTML type looks better than Photoshop rendered type.

<comment><USER26> I purposefully chose to ignore subpixel antialiasing because it's complicated and you have little control over how it works. It's done at a layer further abstracted from the source file, so you can't accurately pixel-fit anything to a subpixel. It's also just another hack, using a smaller unit than a half- pixel, and, like most hacks, it has some serious negative side-effects.

<comment><USER27> He's not suggesting that you subpixel antialias manually. He's pointing out a benefit of leaving your images as vectors: the browser knows the subpixel order of the display, and can make the image prettier than you can without that information.

<comment><USER28> It can make it effectively higher-resolution than you can, but that doesn't mean it can make it prettier. It could still look end up looking worse (from the color bleeding effect, for instance).

</comment></comment></comment></comment><comment><USER29> A small tip here: if instead of using 2d vectors like Illustrator, you use 3d vectors like Blender for your logos and icons. Then the smooth shading of the 3d objects (versus the opaque shading 2d styles usually go for) makes these manual hinting problems meaningless. So 3d vectors are much easier to scale automatically than 2d vectors, without worrying about quality loss.

So many choose 2d logos and icons instead of 3d, simply out of style. But this little advantage is certainly something to at least consider.

</comment><comment><USER30> If you prefer a video:

[http://methodandcraft.com/videos/pixel-hinting-vectors-in- ph...](http://methodandcraft.com/videos/pixel-hinting-vectors-in-photoshop)

</comment><comment><USER31> Fireworks have had a nice little feature for a while

Apple+k and it finds the nearest pixel.

It's doesn't always do good, but sometimes it's just what the doctor ordered.

</comment><comment><USER32> Vector icons tend to look horrible at small sizes. A post from a month ago:

[http://www.pushing-pixels.org/2011/11/04/about-those- vector-...](http://www.pushing-pixels.org/2011/11/04/about-those-vector- icons.html)

<http://news.ycombinator.com/item?id=3720363>

</comment><comment><USER33> Also note that SVG logo's are rendered far better than a scaled down pixel version. I tried a lot of different reduction methods but the SVG version was always "sharper". Just include it in your image-tag: <img src="logo.svg" alt="my logo">

I think you can use a background image as fallback.

<comment><USER34> I find it is easiest to use javascript to set fallbacks.

</comment></comment><comment><USER35> Anyone feels this everlonging problem is related to autofocus ? Pretty sure it wouldn't be very hard to automatically realign subparts to fit based on Fourier analysis.

</comment><comment><USER36> I really wish Fireworks or some image editor was designed for asset creation first and took care of these kinds of issues. Even with Fireworks if you zoom in on the palette and draw a box you can end up creating it on the half pixel and get anti aliasing issues. I want a tool that restricts you to whole pixels for everything, including when it does automatic resizing.

<comment><USER37> Can you clarify your issue with Fireworks? By "palette" do you mean "canvas"? From my experience, there are no sub-pixels initially on the edges of boxes drawn in Fireworks. Sub-pixels will occur if you use the Scale tool (Q) to resize the box, however you may subsequently snap the box to full pixels using Cmd+K. Also, if you resize the box using the X/Y dimension inputs in the Properties inspector, the edges will remain at full pixels.

<comment><USER36> Here you go, I created a box, zoomed in, and resized it using my cursor. <http://i.imgur.com/Nx0Bx.png> The pixel dimensions show whole numbers. Punching in numbers into the properties inspector isn't always an option, for instance when you're trying to resize a box with rounded corners while preserving the corner radius.

<comment><USER37> I see, so it's after you've created the box. I agree that there should at least be a mode where everything snaps to a full pixel. Anyhow, the Cmd+K trick would be useful in your case. Also, corner radii should be preserved if you resize with the properties inspector.

</comment></comment></comment></comment><comment><USER38> This seems like it could be automated algorithmically — it looks like an optimization problem where you want to minimize the number of partially-filled (e.g. "gray") pixels, especially along vertical and horizontal lines.

For rectangular shapes, even a simple repositioning could do a lot.

<comment><USER15> That's automated hinting, it's available in TrueType, Freetype and professional type design software.

</comment></comment><comment><USER39> This article reminded me of an article by Juan Vuletich about the application of signal processing to anti-aliasing:

<http://www.jvuletich.org/Morphic3/Morphic3-201006.html>

I'd say there's still work to be done in this area.

</comment><comment><USER40> While this has the attention of some of the best designers, I'd appreciate a real quick look at our logo for criticism, it's here: <http://www.verelo.com/images/logo.png> (is it using anti-aliasing?)

</comment><comment><USER41> I'm pretty sure this is what drives me nuts about the kickstarter logo. It could be so much crisper:

<http://www.kickstarter.com/images/kickstarter-error.gif>

<comment><USER42> Facebook's too? Especially juxtaposed with all of the crisp white text?

</comment></comment><comment><USER43> Very interesting. Reminds me of pixelsnap, an Inkscape plugin my brother wrote to do this very thing: <http://code.google.com/p/pixelsnap/>

</comment><comment><USER44> I hate to break it to the guy, but I can't remember the last time my browser was at 100% zoom, so his perfect pixels will never look perfect on my screen anyway...

</comment><comment><USER45> That doesn't look like something you can't automate for most of those cases.</comment>


HybridCluster Allows Hosters to Differentiate - <AUTHOR> http://www.hybridcluster.com/blog/hybridcluster-allows-hosters-to-differentiate-sell-new-services-drive-up-margins/

<comment><USER2> Was going to comment that the title here felt misleading since article read like straight up PR, but someone's changed the title.

<comment><AUTHOR> Sorry about that, the title came from the news source that published my interview. I picked the quote from the article for the HN title because I thought it was much more interesting ;-)

</comment></comment><comment><USER3> Can you talk more about your stack? Are you running ZFS on Linux? If so, what's your experience with that combination?

<comment><AUTHOR> Hey! We're actually running ZFS on FreeBSD: the HybridCluster stack is built on FreeBSD jails. We're looking closely at ZFS on Linux though - when we started work on our HA stack ZoL wasn't nearly ready, but now it's looking promising - so we're going to be working with Brian Behlendorf on that. If/when we do a Linux port of HybridCluster, we'll be looking at using Docker for the container part, so HybridCluster could be stateful HA Docker with live migration before too long ;-)

In other news, we're gonna be hosting open-zfs.org on behalf of Brian, Delphix, Joyent and all the other community contributors. Keep an eye out for that, we'll be announcing it on HN as soon as it's ready.

</comment></comment><comment><AUTHOR> Love to answer any questions ;) HC is ZFS + Twisted = Awesome</comment>


"Why I'm Posting Bail Money for Julian Assange" by Michael Moore - <AUTHOR> http://anonops.blogspot.com/2010/12/why-im-posting-bail-money-for-julian.html

<comment><USER4> Same story:

<http://news.ycombinator.com/item?id=2007494> \- michaelmoore.com - <USER3> comments

<http://news.ycombinator.com/item?id=2004894> \- dead - 1 comment

<http://news.ycombinator.com/item?id=2004060> \- dead - 6 comments

<http://news.ycombinator.com/item?id=2003989> \- huffingtonpost.com - <USER3> comments</comment>


Show HN: A different kind of coloring book for kids (Android). Simple and clean. - <AUTHOR> http://samocolors.com

<comment><USER3> Looks well done, but it seems fairly similar to a lot of other apps in the same space: "look, ma, flood fill!". That, or the big, fat "pen" that's possibly even more difficult to do anything useful with for little fingers than a real pencil or crayon.

In other words... I'm still not convinced that tablets or phones are very good for "coloring" or "painting" for children. That's not really a knock on your app, which seems about as good as these things get, but more of a call to use the devices in a new and interesting way that lets kids be creative and makes the most of the features the devices have, rather than emulating (poorly) something that works ok in the real world.

<comment><USER4> David, need your help with something. How can I reach you?

<comment><USER3> Clicking on my profile brings up a variety of sites and things, most of which have contact information. I am always happy to correspond with people!

<comment><USER4> Uh! Ya I did look at your HN profile; and also visited your personal website. Have reached out via twitter, because your email wasn't listed here. Catch up there :)

<comment><USER3> My personal website has a big 'contact' section at the top of the page, with several email addresses. That's your best bet for anything more substantive than 140 characters...

</comment></comment></comment></comment></comment><comment><AUTHOR> This my new Android app. I really tried to make it simple, beautiful and not annoy the kids and their parents with ads. Though I am not sure what is the best strategy to add in-app purchasing and still be nice to users.

<comment><USER5> My daughter is 3 and she enjoys the coloring apps on my iPhone. We have a few that I downloaded for free, one was on sale, one has IAP and one is ad- supported.

The ad-supported one shows ads in a separate "pick your color" UI and I'm happy with the design. It's a flood-fill app like yours and while the drawings aren't as good as yours it's functional enough.

The one[1] with IAP is a "color in the lines" style app with a lot of UI: Picking brushes, viewing past drawing and picking a drawing are pretty rich. I ended up springing for the IAP (probably the first time I've ever indulged in it; there's probably a marketing lesson in there somewhere). The app showcased a bunch of locked coloring books that my daughter kept asking me about, so I bought them so she had more to do in the app. One interesting thing was that they partitioned the app's IAP. You could buy one set of markers, or collections of books for a certain amount, or buy the entire IAP library for a marginally higher price. For the record, I found the IAP design to be ok. The price is a little higher than what I'm personally accustomed to, but not unreasonable. What _does_ bother me about this app is that it continues to show me ads for other apps by this developer. Please don't do that.

Hope this feedback helps you decide how to design your IAP.

Let me also add that it's mind boggling how the iTunes UX designers decided that IAP descriptions should be truncated.

[1] [http://itunes.apple.com/us/app/amazing-coloring- studio/id507...](http://itunes.apple.com/us/app/amazing-coloring- studio/id507378571?mt=8)

<comment><AUTHOR> Thank you for the feedback, I really appreciate it!

</comment></comment></comment><comment><USER6> A tip for other parents who let their kids use their Android phones or tablets. You can lock the Play Store so a pin is needed to do purchases. This also locks in-app purchases.

Older Android Markets did not have this options so I had to learn about this the hard (expensive) way.

<comment><USER7> There's a free app called Famigo Sandbox which will provide your kid with their own launcher with a subset of apps you've approved for their use. As well as in-app purchases, it also prevents making phone calls, sending texts, mucking about with your settings etc. and blocks ads until you unlock with a swipe pattern to get back to the full phone.

It's quite handy. I assume they make money via recommending kid focused apps to their users.

<http://www.famigo.com/sandbox/>

<comment><USER8> Thanks for the shout out, it's always great to hear from a happy user!

You are correct on the business model; right now, it's promotional fees from developers plus device manufacturer licensing fees.

You are also correct that we focus on a different use case than Kyte. It seems to me they're more focused on location and telephony (very worthwhile, btw!), whereas we are all about making it for kids to find and play great apps.

<comment><USER9> I was looking for family safety software for Android, so thanks for the recommendation above. I liked your password entering setup :) What is it called?

</comment></comment></comment></comment><comment><AUTHOR> UPDATE: All BUY and RATE buttons were removed from all sets. Only all-in-one unlock is available in welcome screen and it enables everything forever. I want you and your kids to be happy. Enjoy! New version 1.0.2 should appear on Play Store in moments.

At this point I must say that Android is awesome in a way I am able to provide quick updates. Love it!

</comment><comment><AUTHOR> Thanks for all the feedback guys! App like this should never replace real thing! My wife is children book illustrator (and created the first set with animals) and she draws with our son on paper a lot. This app can help you in certains situations, where you need to entertain your kid for a while and phone is the thing you always have. I am also getting mixed feedback about buy buttons, so I will experiment tonight and will bring better solution which will be even less annoying. If you have good examples or suggestions, I'll be happy to see them!

Thanks again.

<comment><USER10> > I am also getting mixed feedback about buy buttons

Personally, I prefer approach where there is a free version with ads, and a non-free version with _no_ ads and _no_ buy buttons.

Alternatively, some apps simply have the full version ad-free and buy-button- free, and you can optionally buy a "support the developers" version from the store. If the "support-app" is installed, the full version simply adds a "thank you!" on the launch screen.

I don't know how well these approaches do in sales statistics, but I personally go for products like those if given a choice, and I always pay for them if I use them. If nothing else, it's more straightforward and honest.

It is very frustrating to have a _fun_ or _useful_ app which is only provided as a free version and constantly annoys me with buy buttons and ads. I _want_ to just pay - sometimes a lot - for the product instead of watching ads and being nagged to buy Koynz(TM).

<comment><USER11> What ads in children's app?!

<comment><USER10> Car loans and mortgage offers, for some absurd reason. Probably targets my Google account. Consequence of the "monetize by throwing some ads at the user" insanity I guess.

Anyway, I was talking about apps in general. Any well-designed casual game is popular among kids.

</comment></comment></comment></comment><comment><USER6> It looks really nice!

Since you seem not to use the menu for anything: You could disable the legacy menu button on ICS devices by setting the targetSDKVersion to 14 or higher. But do not forget to test your App on an ICS device. By setting the targetSDKVersion so high you tell ICS to disable certain legacy compatibility behaviour.

Partly documented here: [http://developer.android.com/reference/android/os/Build.VERS...](http://developer.android.com/reference/android/os/Build.VERSION_CODES.html)

<comment><AUTHOR> I've already played with that, but it had bad side effect on something (I can't remember what exactly that was). I am going back to that in next updates.

<comment><USER12> IIRC, building for 14 or above enables hardware acceleration for everything automatically: that can cause problems. Try disabling it manually in the manifest.

</comment></comment></comment><comment><USER13> Have you done any usability testing with little kids? I'm intrigued to know if they'll be able to instinctively navigate through the options. Also, isn't using the hardware back button is going to end up with countless accidental app exits?

<comment><AUTHOR> I tested mainly on my 4y old son and then asked few friends to test on their kids. No problems reported. Re HW button - I am thinking about design without it especially because I am going to build iOS version that doesn't have one.

</comment></comment><comment><USER14> I think this app (although nice looking) misses the point of coloring book exercises. I think that using a pen/cil to color is not only aimed at fostering kids' creative process but also developing their hand-eye coordination and improve on their focus. I dont really have the time to dig out the references for this right now.

An additional side effect of this app is that now coloring takes less time. A great feature of coloring books is their ability to "buy" you (the parent) 30-60 minutes of peace.

</comment><comment><USER15> Isn't coloring supposed to train fine motor skills in children? Just using a 'tap and fill' functionality takes that completely away from them :(

</comment><comment><USER16> Very clean UI. I like how you can still do the traditional strokes. The touch to paint can be fun for older kids. This is definitely different from the typical coloring apps.

One suggestion: You should seriously consider iOS if you haven't already. While the Android market desparately needs apps like this, your engagement will be through the roof on iOS since you've designed an app that caters to the tastes of a typical iOS user.

Monetization: I'd recommend pricing it at $1.99 & having a sale weekend during which you give it away for free. Check out this terrific write up for details. I think it was on HN. [http://www.1312.ru/blog/Pocket-Lists-sales-13500-in- first-3-...](http://www.1312.ru/blog/Pocket-Lists-sales-13500-in- first-3-months/)

</comment><comment><USER17> I don't understand what makes this a "different kind of coloring book". Because it has flood fill?

<comment><USER18> I think because of the zoom feature...at least that's what caught my eye as relatively unique.

</comment></comment><comment><USER19> Father to a two year old boy who loves playing with my iDevices.

Firstly, can you tell me in simple terms what's 'different' about it? Amazing Coloring Studio by Linqsoft Ltd. for iOS appears to be very similar. I understand yours is Android but is that really a differentiator anymore?

As for handling kid proof in app purchases, the popular 'Elmo Calls' app for iOS has a fantastic system which is a barely visible slider on the top of the screen which gives access to the in-app purchase menu.

Good luck with it regardless, I'm always keen to see people build decent apps for kids.

<comment><AUTHOR> I tried dozens of them on Android. They are so busy, terrible UIs, ugly pictures, ads... so that's where I want to fight - with a nice thing. Thanks a lot for tips on apps, I'll check them out.

</comment></comment><comment><USER20> just a little app for kids, but very polished and excellent execution. Free and no ads. It's refreshing to know someone is still doing stuff just for fun and share it

</comment><comment><USER21> I'm sure kids will like this but that doesn't mean thats something they should use. Sure some kids (someone mentioned a kid with down-syndrom) will benefit from such an app but I would prefer if my own kids would use real pencils/paper instead so they won't be limited by the application. Of course the results won't surely look as nice but I think it will benefit the creativity of kids to use the real world tools.

</comment><comment><USER22> Just a tip on the "Buy" feature:

Kids will instinctively mash the button 40 times to buy something. You need a more complex stop.

Also, most of the fun of coloring books comes from discovering the weirdness that happens from the overlaying strokes. The strokes are too flat, and they don't "coat". You should add some brush "wetness" and add thickness with successive overlying strokes.

<comment><AUTHOR> There is of course short time between taps which if exceeded, then the tap counts is reset. I'll think about another unlock, I'll just collect the feedback and decide. I've got some feedback on overlaying strokes, so I'll think about it for sure. Thanks for the tips!

</comment></comment><comment><USER23> Nice job! Looks awesome! Will have to try it out with my little one. I haven't seen the other apps that people say are similar, and kind of surprised by some of the not-so-positive comments. As far as real coloring books vs apps - <USER2> really don't see the dichotomy. I think kids are going to grow up with a mix of both, fulfilling different needs/purposes. Kudos!

</comment><comment><USER24> Awesome. I have tipitap Coloring, but the colors are a little difficult to select.Yours is very simple with large selectors (especially on a tablet!) and the drawings look very good. Congratulations! My kids will love this.

</comment><comment><USER25> Doesn't flood fill defeat the point of coloring books? The kids will never learn the hand-eye coordination necessary for drawing within the lines.

</comment><comment><USER26> Looks very polished and easy too use. Gotta test it on my nephew :)

Did you create the images yourself?

<comment><AUTHOR> I did all the graphics, programming, etc. My wife (she is children book illustrator) created the animals set and will create more. Others are licensed from other profesional illustrators from stock sites.

</comment></comment><comment><USER27> What would be the recommended age for kids to play with this? My daughter is 17 months old.

<comment><AUTHOR> From experience with my son (now 4y old) I think it's about 2 years. But if parent will assist, kids learn quickly :-)

</comment></comment><comment><USER28> Why no iOS?

<comment><USER29> Seriously? He just launched, and there are good reasons to start with Android, especially if you don't already own a Mac.

<comment><USER30> Moreover, going off the discussion on the KytePhone app yesterday, Android offers the chance of hardening your device more thoroughly against curious little fingers.

That, and the lower price-point (particularly if you by an off-contract phone, ~AndroidTouch, on ebay), is a clear win for developing kids stuff on Android.</comment></comment></comment>


Stick bomb - <AUTHOR> http://en.wikipedia.org/wiki/Stick_bomb <comment><USER2> Never thought I'd be sharing an A-Trak video on HN, but there's a nice implementation of these in this video: [https://www.youtube.com/watch?v=_GbYR5Aud4Y](https://www.youtube.com/watch?v=_GbYR5Aud4Y)

<comment><USER3> I saw some good places where cuts might be made, I doubt the entire video in one pure take. A behind the scenes video would be great.

<comment><USER4> Here is the behind the scenes video of that cool ass A-Trak video for 'Tuna Melt': [http://youtu.be/fwTOxGKlHvo](http://youtu.be/fwTOxGKlHvo)

<comment><USER3> Creators confirmed in the comments that is was stitched together from many takes. When I watched it again, cuts became pretty obvious.

</comment></comment></comment></comment><comment><USER5> One of the most pleasant web pages I've read on the Internet in a long time:

[http://lunatim.com/kinart/stickhistory.htm](http://lunatim.com/kinart/stickhistory.htm)

I even get an earworm from some of the videos .. ;)

<comment><USER6> That's was like a step back in time! I wish more web content was awesome and provoking like that

<comment><USER7> It was so gradual that I didnt notice when this style of webpage disappeared.

<comment><USER8> It's still out there, it's just drowning in a sea of linkbait, lazy reportage, even lazier "curation", and other bullshit.

</comment></comment></comment></comment><comment><USER9> Can't be done with lego technic bricks. [http://www.pasteall.org/pic/show.php?id=67816](http://www.pasteall.org/pic/show.php?id=67816)

<comment><USER10> That's clearly the wrong way to try it, but I doubt even lowering the sides to the low plane would help.

<comment><USER10> Sorry, I was wrong. I can only guess that the fixings confused me.

</comment></comment></comment><comment><USER11> Because this video perhaps. [https://www.youtube.com/watch?v=PvQ9InhEKu0](https://www.youtube.com/watch?v=PvQ9InhEKu0)

<comment><USER12> this is awesome!

</comment></comment><comment><USER13> Great, now popsicle sticks will get you in trouble at TSA checkpoints.

</comment><comment><USER14> When I was a kid I would make something similar out of a (partially) unfolded paperclip. Seeing it on youtube makes it seem much less amusing than I remember.

[https://www.youtube.com/watch?v=mKaR8cxS4Y4](https://www.youtube.com/watch?v=mKaR8cxS4Y4)

<comment><USER15> I used to do those as well, but without making the ends parallel, just hooking the tips together. To set it off I'd drop it parallel to the plane of the clip instead of on the edge. The goal was to hit the ceiling. One time I actually got it to stick into the fibrous ceiling tile. The challenge of maximizing the force was what made it fun.

</comment></comment><comment><USER16> It can be as fast as a subaru [http://giffare.com/gifs/32799-rc-subaru-wrx- races-a-stick-bo...](http://giffare.com/gifs/32799-rc-subaru-wrx-races-a- stick-bomb)

</comment><comment><USER17> My toddler's favorite toy is a huge box of craft sticks. Now it will be my favorite toy as well.

</comment><comment><USER18> While we are at it: [https://www.youtube.com/watch?v=z7RaPRmxY5I](https://www.youtube.com/watch?v=z7RaPRmxY5I) This clip must have taken ages to set up, film and reset... Very well done!

</comment><comment><USER19> So _that_ is what those are called!

<comment><USER20> You mean _xyloexplosives_?

</comment></comment><comment><USER21> [https://www.youtube.com/watch?v=jiWxU3jXOFc](https://www.youtube.com/watch?v=jiWxU3jXOFc) is cool

</comment><comment><USER22> Is there a nomenclature around the patterns used? Anyone got a good site?

</comment><comment><USER23> As a kid in the 80s, I used to make these kind of structures out of old lollipop sticks you'd find around the streets in summer time. Would make into 7-8 sticks into a kind of star of david shape, which was excellent for a) throwing like a frisbee b) exploding on impact.

Simple times! No idea who taught me how, or what they were referred to, but boy did I have fun

</comment><comment><USER24> When the kids were into crafts, I made one of these for fun - never saw it before, just tried to weave them together with the minimum of sticks. There is a 4-stick 'airplane' possible; the article shows the easier 5-stick version.

So I think its useless to try to find the 'inventor'; endless people have independently discovered this novelty.

</comment><comment><USER25> I know what my 10yo and 5yo boys will be doing over Spring Break next week:

[http://www.amazon.com/Chenille-Kraft-Natural- Sticks-3776-01/...](http://www.amazon.com/Chenille-Kraft-Natural- Sticks-3776-01/dp/B001GXD6BU/ref=cm_rdp_product)

</comment><comment><USER26> This kind of stuff reminds me of these as a child: [http://www.amazon.com/1-5-inch-Rubber-Poppers- Pack/dp/B002R2...](http://www.amazon.com/1-5-inch-Rubber-Poppers- Pack/dp/B002R236SM)

The memories.

<comment><USER27> I bought some of those about a year ago... not sure if the nostalgia's worn off, but the quality of the bounce just doesn't seem as good as it was when I was a kid.

</comment></comment><comment><USER28> good tutorial:

[https://www.youtube.com/watch?v=0lTmFXOkcOc](https://www.youtube.com/watch?v=0lTmFXOkcOc)

</comment><comment><USER29> Oh my god, I used to make these things as a kid! We had a popsicle-stick building contest and while we were waiting for the glue to dry we'd make these and throw them at the other kids' bridges. I had no idea they were actually a "thing". Thank you for posting, brings back memories.

</comment><comment><USER30> A common variation is Cobra Chains or Cobra Weaves. Actually made one today for a college class (go figure?) ...

</comment><comment><USER31> The pitch is easy:

"Xyloexplosives -- like dominos, but made with tongue depressors."

<comment><USER32> And a cooler name.

</comment></comment><comment><USER33> This is awesome. I know what I'm doing with my four year old this weekend. I have been building the triangle bombs with him with paint stir sticks and he loves them.

</comment><comment><USER34> Made these a few years ago, so much fun. Great physical hack!

</comment><comment><USER35> How the hell did i never know about these? So cool! :) Just stumbled upon the SUBARU radio controlled car video an hour ago.

</comment><comment><USER36> Now I know what I'm doing tonight.

</comment><comment><USER37> I just spent way over an hour reading the website and watching videos about stick bombs :o

</comment><comment><USER38> How do you set a stick bomb off? Is there a particular way?

</comment><comment><USER39> Before you know it, the TSA will ban popsicle sticks.

</comment><comment><USER40> physics is so cool sometimes

</comment><comment><USER41> Great, now TSA will take away my sticks.

</comment><comment><USER42> Why is this on HN? Somebody help me out here.

<comment><USER43> Because it's a nice physical hack. I personally haven't seen it before.

Also, because some people (myself included) upvoted it.

<comment><USER44> I have never seen these before. It is nice to see things other hackers consider perfectly normal part of growing up that I completely missed.</comment></comment></comment>


Using Ultrasonic Beacons to Track Users - <AUTHOR> https://www.schneier.com/blog/archives/2017/05/using_ultrasoni.html <comment><USER2> Is there a way to distinguish permission to use the microphone in the foreground vs in the background? AFAIK on Android, no such distinction is made. Many apps have legitimate reasons for using the microphone while in the foreground, but very few in the background.

If there were a simple way to allow foreground use but deny background use of the microphone, a lot of offending apps would be neutered, but I'm not holding my breath for Google to change this, just like I'm not holding my breath for them to allow apps to be silently denied permission by being supplied with fake data (e.g. empty image for camera) so that they cannot refuse to run if denied permission.

<comment><USER3> Apple doesn't make this distinction either. However, they show a BRIGHT RED BAR at the top of the screen any time an app is using the microphone in the background, so it never happens without your knowledge. Seems like Google should at least do that, and letting people block access in the background would be great too.

</comment></comment><comment><USER4> I have been following the progress of this tech for a few years now. People used to take me for a kook but I wish I didn't have a reason to say "I told you so." This is downright scary.

Having trouble finding this list of 234 compromised android apps or any such list. Could anyone point me in the right direction? I would be very sad if my minesweeper app has been listening to ads.

</comment><comment><USER5> Why use ultrasonic beacons instead of cameras and image recognition to track where people walk? It seems like that would be more effective as you don't need customers to have a certain phone, and a certain app, and you probably already have CCTV blanketing your store (at least in Europe).

</comment><comment> gene-h Perhaps one could prevent this by restricting said apps from using any frequencies above a certain bound.</comment>