How I designed a practical electric plane for a NASA competition - <AUTHOR> http://spectrum.ieee.org/aerospace/aviation/how-i-designed-a-practical-electric-plane-for-nasa <comment><USER2> I work at NASA primarily supporting our aeronautics programs, and I'm excited about all-electric and hybrid-electric civil aircraft conceptual design analysis and optimization (for both fixed-wing and rotary-wing). It's one of the big "what-if" areas that is being looked at by NASA aeronautics in the next decade, and an area that has a surprising diversity of intuitive reactions within the industry at large.

Meaning, there is a camp if industry experts that feels that it is a dead end, and another that sees it as a practical way forward. My opinion is that there are gains to be made there, but practical systems will have to be designed and optimized in a far more integrated manner than how most civil aviation systems have been in the past (integrating, for instance, the design optimization of the propulsion, airframe, and mission profiles together at mid to high fidelity early in the conceptual design process).

<comment><USER3> > feels that it is a dead end, and another that sees it as a practical way > forward

Until the Wh/kg ratio of batteries improves significantly, it will be a huge problem to have electric planes. Look at the energy contents of 1 litre of Jet-A or avgas compared to the same weight in batteries. Hydrogen + fuel cell systems to achieve the same energy density require very costly extremely high pressure tanks and fueling systems, and that is before you get into the argument of whether hydrogen is a terrible use of energy.

If your hydrogen supply is coming from an electrolysis process an IMMENSE amount of kWh has been consumed to fill your hydrogen tank, which should be considered for the total environmental cost. So unless your electrolysis plant is hooked up to a massive PV array or a 4GW nuclear power plant, the economics are questionable.

for comparison:

lithium ion batteries 0.36–0.875 MJ/kg

Jet-A: 42.80 MJ/kg

<comment><USER4> What efficiency is the engine converting those 42.80 MJ/kg into power at? I know it's still far above batteries, but what's the actual level batteries have to reach to be competitive in the power to weight ratio? Even that's not the full picture though, as for a system like this you would presumably include the engine weight for an engine that could produce comparable output, but that makes it more complicated.

</comment></comment></comment><comment><USER5> A very enlightening read and quite excellent in breaking down the approach and technologies researched and employed in the concept! I'm an amateur in the arena[1], albeit with some first-hand flight experience, but study this kind of development every chance I can get. As an academic concept, this is superb and the aerodynamic advantage of the prop/tail design deserves high praise - that's some innovative thinking right there!

From an implementation standpoint I'm curious to how practical using a fuel cell will be from an aviation safety and regulatory standpoint. From what I've read regarding their implementation in automobiles, the testing is rigorous, so that's a plus! The author does point out that the plane needs to be accepted by the target markets, and honestly, I think the plane could be built and working by 2020 but there'd be a total of six mechanics qualified in the world to work on the thing. It might be an exaggeration, but give it a little consideration.

We're talking a significant overhaul - an advancement, sure! - to the existing notion of flight. Hey I'm cool with it if it works! I've got no love for burning tons of fuel in the upper atmosphere. Yet also I've been quite skeptical of all the excitement around electric battery tech - e.g. graphene, super-capacitors - until it starts getting used and tested in real world applications. Advancements are underway, sure; time will tell if they live up to the hype though. See also: Moeller Air Car. There's something to be said for the punch that Jet A still packs - the new FlyBoard air debuted recently and I'm not sure an electric version is possible yet, or within the near future.

[1] I participated in the LocalMotors LITECAR challenge and still am sore that an "exoskeleton" and "body panels made out of this lighter metal" entries were deemed more revolutionary than an organic composite sedan powered by microturbines and electric motors because what was _said_ was the purpose of the contest did not match what was _chosen_ in the long run. Grr.

<comment><USER6> _There 's something to be said for the punch that Jet A still packs_

Personally I suspect that the US Navy nuclear-powered CO2-to-JetA system, or something like it, will be the long term solution when fossil JetA becomes prohibitively expensive. Electric prop planes are feasible but electric jets really aren't.

<comment><USER7> When I read this article and also when I see quadcopter endurance tests (just over two hours) I come to the same conclusion as you do. Electric jets aren't happening.

So it is so strange and fascinating that Elon Must seems to think that it could be done.[1] Like: if we take todays lightest and most aerodynamic sail plane, add batteries and an electric motor, and it's still worse than a cessna [2] - how exactly does he reach the conclusion that electric jets, _vertically starting and landing_ _jets_ , are feasible? I really wish for something like the hyperloop design-docs to explain the thinking behind it :)

[1] e.g. [http://bgr.com/2016/02/07/elon-musk-electric-jet-great- idea/](http://bgr.com/2016/02/07/elon-musk-electric-jet-great-idea/) \- "Well I have been thinking about the vertical takeoff and landing of an electric jet a bit more," Musk said. "And I think I have something that might be close. I'm quite tempted to do something about it."

[2] MEA: [https://www.iei.liu.se/machine/applications_re?l=en](https://www.iei.liu.se/machine/applications_re?l=en)

</comment></comment></comment><comment><USER8> I have practical market experience on building a two passenger electrical aircraft and trying to market it, what I found is that "range anxiety" is a real issue for pilots and the market today for electrical planes is really limited to trainers, so we decided to modify our aircraft to an hybrid configuration.

<comment><USER9> As a private pilot: yes, you absolutely do not want to be landing on empty. Range is the same thing as endurance, and endurance means you have options when things don't go your way. Endurance is already a concern even on conventional motors - your average Cessna 150 only has a useful payload of 344 lbs with full fuel tanks. If you want to put two people in it, you're not taking off with full tanks, especially once you account for possibly thinner air above sea level or due to warm temperatures.

You need to keep a minimum (!) 30 minute reserve of fuel for VFR. The 150 has a 4-hour max endurance with full tanks. Usually you get less, because that doesn't include full-throttle time for takeoffs/climb. So if you take out half the gas (buying yourself another 76 lbs of payload) you've actually removed about 3/4 of the useful range of the aircraft. The same problem applies to battery-driven electric aircraft - extra weight kills endurance, and compensating for this causes a death spiral.

Twin-engine aircraft are really the way to fix this, but they're more expensive to get certified for, more expensive to run, more expensive to insure, etc. I'm a big fan of the Diamond DA42, twin diesels are cool as hell and it's totally nuts how slowly they sip fuel.

The other thing not mentioned in the article is that with batteries, as you drain them the output voltage also drops. That translates into reduced torque/power, and possibly an aircraft with different handling characteristics in stall situations. Conventional engines will deliver 100% power on-demand right up until they're out of gas.

<comment><USER10> The voltage droop isn't as bad as you'd think, I don't get limited power until I'm below 10% in our Tesla 85D. Even "full throttle" for most electric motors isn't near the max C rating(because amps = heat = power loss).

The rest of the stuff thought, yeah that's an issue and I feel like one of the areas where Fuel Cells might actually be applicable(you don't have the long- term leakage/storage/fueling issues as with cars).

<comment><USER9> An aircraft can't afford to be hauling around 2-3x as much battery as is actually necessary to fly, as is common in electric cars. I can assure you than when an electric airplane is at the limit of its range, its performance characteristics will change in a negative way.

Electric planes are already at a 100x disadvantage in terms of Specific Energy - liquid fuels (JP-1 jet fuel or gasoline) contain about 46 MJ/kg while Li-ion batteries contain about 0.36-0.875 MJ/kg. They cannot afford to make that a 300x disadvantage. It doesn't work in terms of lift.

As someone else posted in a thread, electric power already takes you from a 900 mile range to a 150 mile range. 50 miles is not acceptable because you're talking <30 minutes of endurance including takeoff, and you have zero safety margin if something should go wrong.

</comment></comment></comment></comment><comment><USER11> This article has me thinking about hybrid electric aircraft (is anyone working on that?). A small internal combustion engine could generate electricity to charge the batteries to run electric motors. With this set up, you could still get the efficiency advantage of the alternate propeller placement. The engine could be much smaller and lighter than it is conventionally because the additional power needed for take-off and climb thrust could be temporarily drawn from batteries. Further, in the event of engine failure, you would still have battery power available to the propellers for a short time in order to make an emergency landing.

<comment><USER12> It's definitely being worked on. Google "hybrid electric aircraft" and you'll find some discussion of the efforts.

It's less advantageous than it is for a car. For one, the difference between maximum power and cruise power is far lower in a typical light airplane than it is in a typical car. A Prius might max out at 130hp but cruise at 25hp. A light airplane often cruises at around 75% of maximum power. Another problem is that the hybrid powertrain adds significant weight, which hurts efficiency much more in airplanes than it does in cars. I don't think these kill the advantages entirely, but it's probably why it's not as far along in airplanes as it is in cars.

<comment><USER13> Right, the first thing to always remember when you're doing a hybrid is that you're stating up-front, "I want to have two engines in this machine -- that's a weight and space cost that I want to pay up-front." As mentioned by the article, with airplanes when you increase weight everything has to get bigger to accommodate it. That doesn't make it impossible, but does make it a bit tricky.

Another interesting question: the fuel cell design in the original post is probably not reversible, is it? It would be really cool if given 10-20 more years of work we then used variable-pitch propellers with reversible fuel cells allowing for a plane which, during descent, could regenerate most of the energy used to make its ascent. It might also make pilots less worried about limited range, because they'd know that in a pinch they could get some more energy to the battery.

<comment><USER14> > allowing for a plane which, during descent, could regenerate most of the > energy used to make its ascent

The Pipistrel aircraft do almost exactly this. They claim about 10-15% energy recovery rate for thier regenerative systems. No need for variable pitch either; they simply windmill the main prop.

</comment></comment></comment></comment><comment><USER15> Fuel cells are energy inefficient. The future of electric air craft is elon musk's vtol super sonic design.

[https://medium.com/@andrewt3000/what-do-we-know-about- elon-m...](https://medium.com/@andrewt3000/what-do-we-know-about-elon-musk-s- electric-plane-design-981e704f59a3#.n5s0jmadr)

</comment><comment><USER16> Why would people would consider electric for airplanes? You want maximum energy density for weight. Jet fuel is pretty damn good when scored like that. We can make synthetic jet fuel from green electricity - if the process uses carbon from the atmosphere it's carbon neutral. Granted it would be expensive, but that's neither here nor there until fossil fuels surpass that price point.

I suspect well-meaning people like the idea of an electric airplane because it's greener, but FYI we live in a market economy. We will continue to extract and burn fossil fuels until it is uneconomic to do so. No matter how many people shout, no matter how much damage it does to the Earth, even if it kills us all. Markets don't care. If you have a problem with that, as I do, the only practical solution is to make fossil fuels not a cost effective alternative. Electric airplanes could be part of a solution - but only if they can compete on cost. I personally like the idea of taxing fossil fuels to factor in the negative externalities - but given the political makeup of the world as a bunch of competing nation-states, it seems unlikely. Game theory tells us there is too much incentive to be the nation state that doesn't support the agreement. Instead what I think will happen is that we'll innovate our way out of the mess by making green technologies more cost effective than fossil fuels.

<comment><USER17> "Fortunately, electric propulsion offers some flexibility that the engineers at Cirrus did not enjoy. Unlike combustion engines, electric motors are compact and efficient. These small, light motors can be placed in many more locations on the aircraft than would be practical for a combustion engine. If applied strategically, this tactic can distribute the power production across more or larger propellers. And the greater the area swept by propellers, the more efficient and quieter they become."

"The decrease in energy consumption and the elimination of the gasoline engine (and all the routine maintenance it requires) will likely reduce operating costs. What's more, the reduction in noise level, from 92 decibels to 76 dB, should improve cabin comfort considerably. And the very high reliability of electric motors should give both pilots and passengers greater peace of mind."

</comment></comment><comment><USER18> Interesting read. I don't have high hopes for hydrogen cars as batteries seems to solve the range problem adequately for most scenarios, and it's easier to build charging stations than hydrogen filling infrastructure. However, for planes it seems that the advantage of low weight is a necessity to electrification. I wonder if the future will be (mostly) electric road transport and hydrogen air transport.

<comment><USER5> Agreed on the perspective regarding hydrogen cars - I never quite figured out the thought process behind trying to make an experimental platform of that type into a mass-consumer product. I mean, I guess it makes environmental sense but the R&D path seemed so long and trying that EVs & hybrids really had a lot of growing up time in parallel.

For me I was always more interested in a turbine system for cars that would use an advanced biofuel (ex: eventual algae-based fuel) which would power electric systems (wheel motors, some batteries, KERS) and sort of convert they existing infrastructure into a more modern one - tanks, pumps, etc.

<comment><USER12> Even from an environmental perspective, hydrogen cars make little sense. Currently, hydrogen is a petroleum product. It's typically made from natural gas, and this process emits plenty of CO2 (plus all the pollution inherent in oil extraction). You can make hydrogen cleanly by using renewable electricity to power electrolysis, but nobody is doing that currently and the efficiency is terrible. You'd need three times as much generating capacity to power a fleet of hydrogen vehicles as you would to power an equivalent fleet of EVs.

I really can't figure out why Toyota is pushing them so hard.

</comment></comment></comment><comment><USER19> >> "Submitted to a NASA competition for students, the design for this electric aircraft had to meet certain requirements, the most important of which was that it could be manufactured within five years."

Is this plane going to be in production?

<comment><USER5> A reasonable question! From my experience with general and professional aviators, the answer is a tentative "No" for quite a while. It would likely start out as an "Experimental" certification by the FAA[1]. Following that, I'm not sure what the course would be to official production for purchase (though Experimental planes can be purchasd on the free market to my knowledge).

[1] [https://www.faa.gov/aircraft/air_cert/airworthiness_certific...](https://www.faa.gov/aircraft/air_cert/airworthiness_certification/sp_awcert/experiment/)

<comment><USER8> The easiest option is to sell it as a KIT where the buyer assembles it and requests certification as an experimental Light Sport Aircraft.

[http://www.kitplanes.com/issues/29_3/builder_spotlight/Under...](http://www.kitplanes.com/issues/29_3/builder_spotlight/Understanding_Experimental_Light_Sport_Aircraft_20376-1.html)

</comment></comment></comment><comment><USER20> This is a fantastic read. But I'm now really curious what things look like at the big end of the spectrum: does the solution scale (or do similar benefits emerge) for 747-scale electric aircraft?

<comment><USER11> I am not an aerospace engineer, so take my comments with a grain of salt.

This will not really scale to the commercial airliner market. The author got most of his improvements out of propeller efficiency, and propellers are very efficient. However, they don't scale to jet speeds. I am not at all certain that an efficient electric powered jet engine could be produced (I suspect the physics just won't support it). If you are willing to take a step back and use hydrogen, I am very willing to believe that an efficient hydrogen powered jet engine could be built, but that would be completely new technology and I would bet it would take decades before it were available even if someone were to start working on it immediately. Besides, it is not clear to me what the advantage of using hydrogen over jet fuel would be. By weight, the energy density is higher, but by volume it is much lower.

<comment><USER21> Hydrogen has problems too. There is a chapter in the Ben Rich book "Skunk Works" on trying to build a hydrogen powered plane and the supporting infrastructure before they did the A12 & SR-71.

</comment></comment></comment><comment><USER22> Having the electric motors at the top of the V tail planes indeed enables a short landing gear. But they increase the tail plane loads, requiring a heavier structure there.

</comment><comment><USER23> I honestly cannot wait until these plane designs become more available .. electric flight would be my preferred way of getting around.

</comment><comment><USER24> So I'm curious -- could a non-fuel cell electric generator (gas, turbine, etc.) make this design perform even better?

</comment><comment><USER25> I was under he impression that fuel cells were very expensive compared to batteries. Is that not the case?

<comment><USER26> The contest required a cost analysis, but had no cost _requirement._

[http://aero.larc.nasa.gov/files/2014/09/2020-E-GA-design- con...](http://aero.larc.nasa.gov/files/2014/09/2020-E-GA-design-contest- ARMD-1.pdf)

<comment><USER4> Yet the author thinks the cost is comparable, so there is that.

 _I was able to arrive at a design that, if mass-produced, could indeed compete with the Cirrus SR22. It would weigh and cost about the same, and its range would be very similar: about 920 miles. The plane's cruising speed would be somewhat less—173 as opposed to 212 mph. But that seems a reasonable bargain, given that the electric aircraft would consume about a quarter of the energy per flight._

</comment></comment></comment><comment><USER27> why not store many small batteries in the wings ?

<comment><USER28> As the article states a few times, weight is the main issue.

<comment><USER27> what part of lithium-ion batteries is heavy ? Lithium is light

<comment><USER29> The rest of them. Lithium is only the electrolyte. They also need cathode and anode materials.

Specific energy of gasoline: 46.4 MJ/kg

Specific energy of high end Li-ion batteries: 1.3 MJ/kg

<comment><USER27> it amazes me that we've achieved so many hard things (going to the moon, to Mars, to Saturn, making computers) and yet batteries are so primitive that we can't even beat gasoline</comment></comment></comment></comment></comment>


Sendwithus (YC W14) Offers A/B Testing And Analytics Tools For Email Marketers - <AUTHOR> http://techcrunch.com/2014/02/07/sendwithus-y-combinator/

<comment><USER2> They are one of the strongest companies in this YC batch. Powerful team with a solid product riding lots of traction.

</comment><comment><USER3> Brad (bvanvugt) and I are pretty excited to be announcing this; I think we're one of the first Canadian companies from BC to be part of YC.

</comment><comment><USER4> The product looks nice. Well done.

To the founders: can you write a bit about how Sendwithus compares to Vero and Customer.io? Also, have you considered bundling an email service provider? I know other companies have some arrangement with SendGrid. It would be nice to not have to go get my own account.

Thanks!

<comment><AUTHOR> Absolutely, and great questions.

Our focus is on content management and optimization for _all_ your transactional email. We find that large successful companies always end up building this sort tool themselves - that's the pain we solve. Both Vero and Customer.io are great tools for triggering very specific emails early on in product development. We provide a full-featured service that solves the needs of larger companies as they grow and scale.

Bundling an email service provider is definitely something we've considered, and may do in the future. For now, integrating with existing ESP accounts has allowed us to completely side-step questions/concerns around deliverability and scale. ie: If a customer of ours already trusts SendGrid, we never spend time convincing them our bundled SendGrid is equally powerful.

That, and most major ESPs have very competitive and capable free tiers.

</comment></comment><comment><USER5> Great product. Definitely going to be using this. Keep up the great work!

<comment><AUTHOR> Thanks bliggy, it's surprising (and ridiculous) how many developers end up building this themselves.

<comment><USER5> I've definitely built this sort of thing at least a few times. There comes a point where it definitely makes more sense to build this sort of functionality (or now use sendwithus!), i.e. when you get tired of hearing about changes to email templates from marketing! At the end of the day making it easier to test and optimize all the communications with your customers no matter how mundane the email is awesome. Just simple things like upsell messaging depending on the user is huge -- and not something a developer generally wants to or is capable of worrying about :)

<comment><AUTHOR> Removing email templates from source code alone is a huge win - to your point, I don't know any devs who enjoy updating email templates :)

We wrote a quick blog post about this a few weeks back: [http://blog.bvanvugt.com/great-b2b-saas-products-remove- tech...](http://blog.bvanvugt.com/great-b2b-saas-products-remove-technical- dependency/)

</comment></comment></comment></comment><comment><USER6> Great idea, it's crazy how many good startup ideas one can come up with while building on their current startup. This is one of them, glad someone built it :)

<comment><AUTHOR> Exactly! As developers ourselves, it's ridiculous how many times we've (begrudgingly) built this functionality into other products.

</comment></comment><comment><USER7> Giving marketing teams the ability to test and optimize transactional emails opens up a new customer referral and upgrade channel. Love what these guys are doing.

<comment><USER3> Not only is transactional email a great referral channel (just look at what Dropbox did), it's also ripe for optimization.

Engagement emails are used by almost every kind of app to facilitate user actions, but by being trapped in source code, the people who care about user experience and metrics can't take action to improve them.

</comment></comment><comment><USER8> Congrats on the launch. I have a question, do you do event based notification like customer.io?

<comment><AUTHOR> Thanks knes! :) We allow companies to control their own triggers via API - more information here: [https://www.sendwithus.com/developers](https://www.sendwithus.com/developers)

</comment></comment><comment><USER9> I found their email template editor to be amazingly powerful yet easy at the same time!

</comment><comment><USER10> Love the idea - solving an important problem

<comment><USER3> Thanks Avlok, we feel sendwithus is an important building block in any modern web app.

</comment></comment><comment><USER11> Awesome product.</comment>


Artifacts alter timeline for Native Americans in California (2019) - <AUTHOR> https://www.sfchronicle.com/environment/article/Discovery-alters-timeline-for-Native-Americans-in-14423617.php <comment><USER2> Also see _Ishi: The Last Yahi_.

[https://www.youtube.com/watch?v=BmZTXWZ_q08](https://www.youtube.com/watch?v=BmZTXWZ_q08)

<comment><USER3> Being from that part of CA, we had classes and field trips about Ishi almost every year through primary school. Such a sad story.</comment></comment>


BS Detector for Developers - <AUTHOR> http://devdraft.com/bsdetector?utm_source=hackernews&utm_medium=blog&utm_campaign=bsdetector

<comment><USER2> We connect people to job opportunities based on merit. Behind the BS Detector is our auto generated scorecard that gives you an unambiguous view of your skills and presents them to companies. No linkedin. No resume. No BS.

</comment><comment><USER3> What kind of BS is this detecting?

<comment><AUTHOR> Tells if a developer is good at software fundamentals.

<comment><USER3> That seems like a pretty negative pitch. "Come to our site and we'll tell you if your skills are BS or not." Usually people want to detect other people's BS, not their own.

<comment><USER2> Thanks for the input. We're testing the message. If you go to our regular site www.devdraft.com, you'll see the original one. Which do you prefer?

<comment><USER3> I prefer the original since it's more positive.

<comment><AUTHOR> Thanks for the feedback!</comment></comment></comment></comment></comment></comment>


The Cube Rule of Food Identification - <AUTHOR> http://cuberule.com <comment><USER2> I'm a sandwich descriptivist rather than a prescriptivist. I know what a sandwich is, and any definition that say that a hot dog is a sandwich or that a sub/hero/hoagie is not a sandwich is a definition that I do not accept.

Similarly, a bagel with cream cheese (that is, both halves of the bagel sandwiching cream cheese) is not a sandwich (despite the use of the word "sandwiching" in the definition), but a bagel with turkey inside is a sandwich.

I'm comfortable without a definition, though I look forward to hearing the reports of the intrepid theoreticians that can yield definitions that satisfy these criteria, much as I laud the efforts of the adjective-ordering folk in descriptive grammar.

My rule of thumb is that if I went into a restaurant and asked the waiter "I want a sandwich, but I don't care what kind -- surprise me!" and they brought me an object, how angry would I be at the waiter who brought me that object.

<comment><USER3> > any definition that say that a hot dog is a sandwich or that a > sub/hero/hoagie is not a sandwich is a definition that I do not accept.

Isn't that still prescriptivism? Descriptivism here would mean noting what people claim constitutes sandwichhood, and maybe noting what people's behavior reveals about what they actually do or don't treat as a sandwich. But it would be prescriptivist to assert a new definition of sandwichhood, even if you argue that it's somehow more motivated than others.

<comment><USER2> By descriptively I mean that I do not believe that we should model our usage after rules which were derived from usage, but instead should examine our usage and attempt to model it.

A prescriptivist says that a pronoun should match the number, gender, and human-ness of its antecedent, and therefore "they" is not acceptable when referring to a single person. A casual descriptivist says that they understand what it means when other people use "they" in a singular fashion, and find that it is a useful construct. A formal descriptivist would try to describe how the usage and clarity is practically evolving over time. The terms "pronoun" and "antecedent" are terms themselves modeled from actual usage, rather than some organizing committee that decided how English should work.

Similarly for sandwich definition. The descriptivist viewpoint says that no strict definition is necessary; that people have a casual understanding and should model their usage on that. A prescriptivist says "here is a definition of 'sandwich' that models a significant number of things that many people agree are sandwiches, so we expand that definition and use that to label things as sandwich or not sandwich, regardless of the common understanding".

The key point here is that I do not feel a strict definition is necessary in order to reasonably discuss sandwich labeling.

Practically speaking, I have found that my heuristic above generally yields agreement from others (in particular, I have not yet found anyone who would be happy with a hot dog under those circumstances), with occasional differences of opinion that would be interesting for a professional sandwichologist to examine as a question of sandwichial drift over time.

</comment></comment></comment><comment><USER4> This gets us classifications all the way from "no starch at all" (i.e. soup) to "non-starch surrounded on all sides by the starch" (i.e. calzone). But I posit the existence of an eighth category... that is to say the inverse of the calzone, which would be "starch surrounded on all sides by a non-starch"? An anti-calzone, if you will. Seems rather rare, but not impossible (e.g. turkey with stuffing).

<comment><USER5> Once, while working in a pizza place I theorized the creation of what I like to call the Dyson Pizza. Sauce, cheese, and toppings completely encircling a sphere of bread.

<comment><USER6> It's appropriate that such a thing could only be baked in space.

<comment><USER7> It's suddenly obvious that not only could this be baked in space, it absolutely will be. This will be a thing when space tourism comes online. I only hope they still call it a Dyson pizza.

<comment><USER6> Quick, someone tell Elon Musk.

</comment></comment></comment></comment></comment><comment><USER8> Sandwiches are like fascism. In _Ur-Fascism_ , Umberto Eco talks about the difficulty of defining the "know it when you see it" category of fascism. We start with a set of concrete examples and we seek to define the category based on the qualities shared by those examples. One example might have qualities A and B, a second B and C and a third, C and D. The first thing shares no qualities with the last, but they all belong to the same category by a kind of transitivity. Sandwich is an agglomeration of qualities that tend to cluster together.

<comment> mark-wagner In his Philosophical Investigations, Wittgenstein's response to this problem are the concepts of "language games" and "family resemblance." From [https://plato.stanford.edu/entries/wittgenstein/#LangGameFam...](https://plato.stanford.edu/entries/wittgenstein/#LangGameFamiRese):

> Still, just as we cannot give a final, essential definition of 'game', so we > cannot find "what is common to all these activities and what makes them into > language or parts of language" (PI 65).

> There is no reason to look, as we have done traditionally—and > dogmatically—for one, essential core in which the meaning of a word is > located and which is, therefore, common to all uses of that word. We should, > instead, travel with the word's uses through "a complicated network of > similarities overlapping and criss-crossing" (PI 66).

<comment><USER9> > > ... We should, instead, travel with the word's uses through "a complicated > network of similarities overlapping and criss-crossing"

This is untenable. It's part of the identity of certain words that they change meaning, but that's the exception. In all other cases you can find a center of mass, so to speak, although describing that with fever words than the word you try to describe is mostly impossible. I need to be able to reject when somebody talks bullshit, like Wittgenstein does there, professionally.

<comment><USER10> It's absolutely untenable for the practical purposes you're after. Unfortunately, that doesn't disqualify it from being true. The more we examine language, the more it seems to be the case that there's really no guaranteed 'centers of mass', that they can shift between corpora, that they are different between times, geographies, social registers, and even between individual people. Some semantic units may be more volatile than others, but they're still all defined relative to each other within the head of a given speaker, and non-rigorously at that. And on top of that, they've got pretty complicated, non-rigorous connections to whatever the driving hardware underneath looks like.

It'd be nice to have some formal process for deciding what's bullshit and what's not. But, it doesn't seem to actually. exist in any objective sense. The words that make the most sense to you are your own. And everyone else always kinda seems like they're full of bullshit.

</comment></comment></comment></comment><comment><USER11> In Czech Republic, we have "sausage in a roll", which is the same thing as hotdog, except they make a hole in the roll (from one side only) and stick the sausage and sauce in it. So you can nicely hold it in your hand like ice cream cone.

Recently, some companies here have started making classic hotdogs. But I never understood why - "sausage in a roll" is so much superior topology (for eating on the run). On the contrary, I don't understand why Americans won't adopt "sausage in a roll" instead.

<comment><USER12> How do you get the hot dog toppings (mustard, relish, onions, etc.) into the hole in the roll?

<comment><USER13> You carve out a hole slightly larger than the sausage. You hold the roll at approximately a 45 degree angle, while spinning it. Thus the hole remains in place, while the bread moves around it. As you are spinning it, you put the toppings in. Then you shove the sausage in (after acquiring enthusiastic consent).

</comment></comment></comment><comment><USER14> This reminds me of the "grilled cheese" v. "melt" debate from Reddit a few years back.

I really enjoy this kind of "ridiculous topic" \+ "hyper-analysis" humor.

<comment><USER15> Reminds me of this game review. I wish I could find the original: [https://forums.beamdog.com/discussion/2959/baldurs-gate- is-s...](https://forums.beamdog.com/discussion/2959/baldurs-gate-is-such-a- terrible-game)

All you have to do is misunderstand the genre of something and then review it as that. I need a YouTube channel about this.

</comment></comment><comment><USER16> Welcome to the wonderful world of Ontology, "the philosophical study of being, [...], existence, reality, [...] and the basic categories of being and their relations". [0]

A narrower related field is Taxonomy, the practice and science of classification.

I like the "cube rule" as a very coarse grained way of classifying food! Classifications of things can become pretty crazy, in particular when they try to classify very general and dissimilar things (example, the schema.org vocabulary [1]).

Now someone should turn the cube rule to an OWL vocabulary so machines too, like we humans, can understand the difference between a hot dog and a salad [2].

0: [https://en.wikipedia.org/wiki/Ontology](https://en.wikipedia.org/wiki/Ontology)

1: [https://schema.org/docs/full.html](https://schema.org/docs/full.html)

2: [https://en.wikipedia.org/wiki/Web_Ontology_Language](https://en.wikipedia.org/wiki/Web_Ontology_Language)

</comment><comment><USER17> I would argue that sandwiches follow a prototype semantic representation in American English. That is, there are a handful of "ideal" sandwiches which are the first thing you think of when it comes to a sandwich. Some items are conventionally not sandwiches. These items might have many similarities with things which are sandwiches, but because of their cultural or culinary significance, are in their own special category. A person may judge an object based on their relative sandwichness which is really a distance metric in which items closer to one of the platonic ideals of a sandwich than they are to a not-a-sandwich are considered to be a sandwich. This way of mentally representing categories of objects, while natural, makes forming precise, rule-based definitions of sandwich classification inherently difficult and inconsistent. Any algorithm for classifying a sandwich must either contain rules which are not universally applied in all situations, or which classifies (or fails to classify) foods as sandwiches which are not conventionally considered sandwiches.

As a non-sandwich example of the same phenomenon, consider whether or not an item is considered to be furniture. A few items are universally considered to be furniture: beds, couches, desks, wardrobes. These items together form a semantic boundary, but that boundary is not necessarily uniform. Having legs certainly matters, but not all furniture has legs. Being not easily movable matters, but chairs are easily moved and if couches are furniture, so are chairs. Likewise, items which are not movable at all, such as shelves built into the wall may not be furniture depending on who you ask. Appliances have electronics, and appliances could be considered a special category of furniture, or simply not be considered furniture. Some people would classify lamps as furniture, but not televisions.

The issue is that semantic boundaries are not symmetrical. Having features which differ from our platonic ideals and our prototypical example of the category are not weighted equally. Some features matter more, and all of those features together form a gestalt of sandwichness. An attempt to form hard and fast rules about which features are necessary to be a sandwich are well- meaning, but ultimately incorrect as they fail to appreciate the psychology of the sandwich, what it means to hold the concept of a sandwich in your head.

<comment><USER18> The way I see it, anything between two other pieces of another thing (separate pieces or conjoined, doesn't matter) constitutes a sandwich. If we accept the origin story (urban legend?) of its origin as invented by the Earl of Sandwich so that he and his friends can snack without getting their hands dirty during card games, then the sandwich can't be defined as a specific food item, but by the act of putting one thing between two others. Furniture is anything used to "furnish" a space. If the shelf was attached to the wall after the wall is built, it's furniture. If it was built as part of the wall, it isn't.

</comment></comment><comment><USER19> I lost it when I got to the Bonus Round... because obviously, a steak is a salad, and soup is a wet salad? I mean how could you not get that...

</comment><comment><USER20> This is an awesome way to explain object-oriented modeling/leaky abstractions to a non-techie.

</comment><comment><USER21> There are a few missing variations that aren't symmetric to one of the 6 existing categories. I wonder if this implies that there are other categories possible that haven't been made yet.

The one with the most possibility is two starch faces, as in (2), but the starch faces share an edge.

<comment><USER22> That's just a degenerate case of the taco.

<comment><USER23> Is a hard shell taco that has split a sandwich?

<comment><USER24> No, there is no acceptable state between burrito and salad. A split taco is an initial demonstration of innate knowledge and some motor control, best done before the staff retreats.

</comment></comment></comment></comment><comment><USER25> No true Scotsman would classify enchilada as solely sushi, when the extra layer of cheese on top puts it in a superposition of being sushi AND toast.

<comment><USER5> I was unaware the Scottish, as a whole, had so much to say about sushi and enchiladas. ;)

<comment><USER26> A Scotch-Egg is a very curious exception to the cube rule. It's a kind of calzone, where edges have been limited, or a kind of 3D toast fepending on your topplogical analysis...

</comment></comment></comment><comment><USER27> I think the real mistake is assuming that the answer to "is this a sandwich" is either "yes", or "no". Something can be kinda a sandwich, or not really a sandwich, or slightly a sandwich, or definitely a sandwich, or not at all a sandwich, or anywhere in between.

Furthermore, there doesn't have to be a consistent set of rules defining what is and what is not a sandwich.

Arguing about it is fun, though.

</comment><comment><USER28> This is because the categories are meant to capture some information about an object, but we expect them to capture all of the information about an object.

[https://www.lesswrong.com/posts/yA4gF5KrboK2m2Xu7/how-an- alg...](https://www.lesswrong.com/posts/yA4gF5KrboK2m2Xu7/how-an-algorithm- feels-from-inside)

</comment><comment><USER29> My friend has a deceptively simple answer to this question:

If you put schmear/spread/sauce on the bread, it's a sandwich.

If you put schmear/spread/sauce on the "meat", it's not a sandwich.

The distinction is that in the latter, the bread is just a vessel to get "meat" into your mouth. In the former, the bread is part of the whole package.

</comment><comment><USER30> TIL: any food not structurally supported by other food is a salad. Like French fries, steak, and milkshakes.

</comment><comment><USER31> The hotdog is classified as taco because it has three sides of the cube but I would argue that a hotdog consists only of two perpendicular sides of the cube because the angle between the buns is only about 90 degrees.

<comment><USER32> critical insight, should be reported to the author

</comment></comment><comment><USER33> I subscribe to the belief that the key feature of a sandwich is it's horizontal alignment and stacking. Therefore a hot dog isn't a sandwich because it's split in the middle, not stacked horizontally.

<comment><USER34> By your definition Subways aren't sandwiches.

<comment><USER33> Actually subs are the reason that the horizontal/vertical rule needs to exist- otherwise we could just use two separate pieces of bread as the rule. A sub is stacked vertically whereas a hot dog is nestled horizontally.

</comment></comment></comment><comment><USER35> Ok, i tried to take it serious, but i'm dying here of laughter. I am still convinced this is meant in a quite serious way, bbut. Gneehehehhahah.... FLAG IT!

</comment><comment><USER36> I understand that many of the examples are just absurdism in action, but I have trouble understanding the resistance to labeling a hot dog as a sandwich.

But on the other hand, my wife likes to troll me by calling buttered toast a "butter sandwich", so maybe some rigor in our definitions would do my life some good.

</comment><comment><USER37> Topologically a toast is the same as a taco and a bread bowl. And a burrito or wrap for that matter.

</comment><comment><USER38> I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description of "sandwich", and perhaps I could never succeed in intelligibly doing so. But I know it when I see it.

</comment><comment><USER23> If anyone is wondering why toast (1) is listed as an example of a sandwich (2)... I recently learned from a kind HN commenter that toast sandwich is a sandwich where the filling is a buttered piece of toast.

</comment><comment><USER39> The definition that I have always stuck with is that a sandwich has leavened bread on two sides of whatever is in the sandwich. Therefore, hot dog is a sandwich, a taco is not, etc.

</comment><comment><USER40> Interesting. It all comes down to topology - of the wrapper (or cover) and the fillings. BTW, what happens if the wrapper itself has filling, for example falafel wrap?

</comment><comment><USER41> Lasagna does not have pasta (its starch component) on the bottom or the top. A wrap (such as a falafel wrap, as it is pictured on the site) is a taco, not sushi.

<comment><USER42> sushi is often wrapped the same as a taco

<comment><USER41> Right, but that's not the point. I am referring the sushi standard defined in the article based on the cube illustration. In reality there is sushi that conforms to nearly all of those designations. Furthermore, tacos are filled, not wrapped.

</comment></comment></comment><comment><USER43> This classification is incomplete without including food with only 1 side, such as the rarely seen "Mobius Bacon".

</comment><comment><USER44> What about the cone? Hand Roles. Ice cream cones. Some crepes. Or is that a type of Soup/Salad/Bread Bowl...

<comment><USER45> Cones are obviously quiches/bowls.

> Some crepes.

Crepes are not trivial to classify: obviously a plain flat crepe with some topping is a toast, a "walkaround" (usually sweet) crepe is a quiche and sushi/wrap crepes exist (e.g. galette-saucisse[0]) but what about the "complète" where the crèpe is folded back on the filling but not entirely? Functionally it's closer to a calzone or a toast (it's not eaten from the "opening") but technically it looks more like a quiche.

[0] [https://en.wikipedia.org/wiki/Galette- saucisse](https://en.wikipedia.org/wiki/Galette-saucisse)

</comment></comment><comment><USER46> See? Poutine and steak are salads! And they said my diet is unhealthy; who's laughing now?

</comment><comment><USER47> I used to believe all theses things were sandwiches. How misinformed was I

</comment><comment><USER48> thus [https://en.wikipedia.org/wiki/Cannelloni](https://en.wikipedia.org/wiki/Cannelloni) are sushi

and real mexican tacos are too

</comment><comment><USER49> Why is pumpkin pie toast but Key Lime pie is quiche?

<comment><USER50> I'm guessing the distinction is down to slice vs entire pie, rather than flavor.

</comment></comment><comment><USER51> So is an open-faced sandwich an oxymoron?

<comment><USER52> Most of the sandwich debate is caused by ignoring adjectives. In the case of a submarine sandwich, it's a sandwich except we apply the adjective submarine to say we are modifying the bread situation. An open faced sandwich is just like a sandwich except we remove the top piece of bread. Which is why a hotdog is not a sandwich. We could have an adjective to say we are modifying the bread and another to say we are modifying the filling, but then there is nothing left of the sandwich portion, which is why we have a new word for it.

<comment><USER53> Whether you call it sandwich or not, the mathematical description of a hot dog is well within the bounds of the mathematical description of a sandwich.

Fiddling about with adjectives is about as useful as saying that squares are not rectangles or rhombuses because otherwise they would be called rhomboid rectangles or rectangular rhombuses.

The hot dog is a special case of a sausage submarine sandwich.

[https://en.wikipedia.org/wiki/Sausage_sandwich](https://en.wikipedia.org/wiki/Sausage_sandwich)

</comment></comment></comment><comment><USER54> You can't argue with this logic!

<comment><USER55> The only thing I'd change is to rename the sushi category to something broader like wrap. Sushi is a really specific foodstuff to me to be the name of that category.

<comment><USER56> I thought the same. Wrap or burrito, though both have the problem that they can be closed at one or both ends, thus changing their category...

The tweet screenshot from @Phosphatide has Japanese along the top, so I'm assuming that's why the immediate reference was sushi.

<comment><USER55> That brings up an even more interesting/disturbing question does a burrito turn into a salad after the first couple bites because one (hopefully only one) end is open now.

<comment><USER57> ?

Thats a taco

It turns into a salad when it falls apart

<comment><USER55> According to the cube rule it would turn into a soup/salad w/ bread bowl. Tacos have 3 open sides a partially eaten burrito has one open side. Burrito -> taco requires a massive structural failure.

</comment></comment></comment></comment></comment></comment><comment><USER58> Is this what HN has become?

</comment><comment><USER59> Let the flame wars begin!

</comment><comment><USER15> I know it when I see it.

</comment><comment><USER60> so, is a lobster a calzone?

</comment><comment><USER9> I have a passing interest in linguistics[3] and so let me tell you, after intensive meditation about the topic I found that sandwich could well be cognate to German "Wecke", a bread bun, supposedly related to 'wedge'. I can't pin point "sand-" yet.

I think that would be crucial to determine the precise meaning. I'm very much against either extreme, pre- or description, but I find that expanding the sample space back to include historic meaning may yield results able to satisfy both sides.

Maybe I can still help out. We are actually talking about the club sandwich. Club sandwich could be, for all I know, which is very little about the club sandwiches history, cognate to Ger. "Klappstulle" (a 2-sandwich [to use the OP's typology] made by folding a slice over) at least the club part, and both could go all the way back to the Proto Indo European root whence glue (to stick together) compare Ger. "Kleber" (glue), "Kleie" (wheat-paste?), and perhaps Old English and Gothic "hlaif" (bread) then most likely in reference to dough, Ger. "klumpen" \- 'clump', 'glob'. A club of people sticks together. The swinging and clubbing club could perhaps compare to 'key' (from Lt. clavis, from a sense nail, peg, hook), as stick, sticky and clavis, claudo show similar relations. "Klappe" means 'hatch', 'shutter', 'mouth', we say something "klappt nicht" (doesn't function), "(um)klappen" ... it's baffling that there's no good translation: The lid of box is a "Klappe", and closing it shut is "zuklappen"; A "klappe" that doesn't shut tight, flaps and makes noise, that noise is called "klappern" and from that all kinds of 'to make noise' "klappern"; Best fit would be 'clamp'. Now it depends at which time, if there was a relation at all, our dinners aligned or diverged. But, since you can't take a Hot Dog to work and eat it later--already cold--it cannot be a club sandwich, at least if folding is done primarily to stack and wrap them without making a mess of it. Well, I made a mess of it, I didn't check references on most my claims, but I'll have to wrap it up.

As a working hypothesis I suppose "sand" relates to Ger. "Kanten", the thick end of a loaf, related to "Kante" (edge), but its Greek root has no secure origin so a link to the celtic word for rim, tire giving "waybread" or "wagonbread" (cp. Ger. "Weg" \- way; "Wegebrot") is not too promising. It's just, I have that image of the thick end bread as a happy hobo's ration very present from cartoons. But a better candidate would relate to butter perhaps. Or how about "Shank", cog. Ger. "Schinken" (ham), "Schenkel" (thighs), as something two sided, angled. Anyone reminded of John Connery? That's ridiculous. How about "to send for" \- Ger. "gemachte Brote". I mean, there was a time and place where ... wasn't common and bread had been eaten raw or at least separately (... "Belag" \- topping, coating).

[1] Wiki Commons has a picture of a ca. 8000 years old specimen in the form of a Spitzwecke [https://de.wikipedia.org/wiki/Datei:Spitzweck_Reko_Oveg%C3%B...](https://de.wikipedia.org/wiki/Datei:Spitzweck_Reko_Oveg%C3%B6nne.jpg)

[2] from Latin canthus ("tire, edge of a wheel"), from Ancient Greek κανθός (kanthós, "corner of the eye, tire, etc."). The Greek is not certain, maybe from Celtic or if that seems implausible not Indo European.

[3] While I don't like anyone prescribing as if they were they majesty, I still dislike the descriptive approach that labels anything as correct that randomly comes up in the mash up of dialects. I'm especially weary of misunderstandings becoming fashionable.

<comment><USER61> [https://en.wikipedia.org/wiki/Earl_of_Sandwich](https://en.wikipedia.org/wiki/Earl_of_Sandwich)

<comment><USER9> I'd still hold that the name stuck because it was at least a funny play of words and probably way older than the earl.

<comment><USER9> the word "send" doesn't seem to have changed much; Meant travel, journey. Sandwich was a landing site for ships, roman beach head and all. So sandwich was kind of ... a postoffice? traveler's office? Just a marketplace and harbour? I mean, compare Stralsunt and tell me that's named for being built on sunt, err I mean sand.

On the other hand, the look and feel of hardtack (which cannot be Tolkiens _waybread_ if that's brown on the outside and creamy on the inside) and zwieback pretty much reminds of sand. And they might sell it to ships leaving port. That doesn't quite figure with how we know a sandwhich today, but sure enough, there are other roots that can derive "sand-".

At any rate, placenames lend much better and hence more often to food names. And placenames in turn have often been related to milling and possibly mill- derivatives; to biblical proportions--cf. Bethlehem--which, again, may mean that bread words overlap with more figurative meanings; compare "sound" (healthy), from PIE reconstruction *swent-~sunt- (vigor); Then compare vigor and -wich ... Townsville might sound redundant, but there it is.

</comment></comment></comment></comment><comment><USER62> I love it!

</comment><comment><USER63> what about pretzels?

</comment><comment><USER64> reading these comments is weird. i interpret this page as a kind of satire of a modern pretentious analytical techie orientation that hubristically "solves" things by creating some alluringly simple model and ignoring all the ways it doesn't work. it adopts the mores and tone of a modern tech talk, and presents its idiotic results with a straight face. so its super funny. a little less funny when you have to explain it to people. people who are taking this at face value- really?

</comment><comment><USER65> While I can appreciate the fun factor, I hope this is not a turning point where HN becomes like Reddit. Get this off the front page please.

<comment><USER66> It seems the distinguishing feature of the joke is that it has its own domain name.

<comment><USER9> The problem is one of significance to machine learning, I believe. 6 DoF for the classification of food within the domain of dough products is ... seemingly too little.

</comment></comment></comment><comment><USER67> These kinds of sites give me anxiety.

It isn't good to see large communities of humans burning mental calories to come to the same set of conclusions (I'm on team sandwich because $REASON | I'm on team taco because $REASON). It is a mental D.o.s. directed towards humans that tend towards herding.

<comment><USER68> Choose team calzone then, the comfort of a wall on all sides may help with the anxiety.</comment></comment>


Google+ launches 'Ripples' visualisation - <AUTHOR> http://www.visualisingdata.com/index.php/2011/10/google-launches-ripples-visualisation/ <comment><USER2> That's very fancy and a great start! I hope more social graph networks release contextualized data like this. Despite the impressive visualization, I still find myself struggling to find the answers I really want:

1\. Path (and distance) that a reshare traveled between the originator and the reshare I'm currently seeing in my stream.

2\. Percentile (and absolute number) of reshares my reshare accounts for. That is, what volume of the total reshare tree my subtree is responsible for.

Bonus: Potential impressions (aka maximum reach) my reshare accounts for by counting the total unique audience for each reshare in my subtree.

</comment><comment><USER3> Built by <http://twitter.com/#!/viegasf> <http://twitter.com/#!/wattenberg> and <http://twitter.com/#/jhebert>

<comment><USER4> Ironic?

<comment><USER5> Why? Last I heard Twitter and Facebook weren't banned on the campus. Each network has it's audience and undoubtedly Twitter is huge.

</comment></comment></comment><comment><USER6> Some interesting ripples:

Steve Yegge's rant follow-up: [https://plus.google.com/ripples/details?activityid=bwJ7kAELR...](https://plus.google.com/ripples/details?activityid=bwJ7kAELRnf)

Steve Yegge Amazon war story #1:[https://plus.google.com/ripples/details?activityid=AaygmbzVe...](https://plus.google.com/ripples/details?activityid=AaygmbzVeRq)

It would have been interesting to see the ripple for the original rant...

edit: Although Steve deleted the post, here's the associated ripple: [https://plus.google.com/ripples/details?activityid=WugKtXSp7...](https://plus.google.com/ripples/details?activityid=WugKtXSp7We)

<comment><USER7> This one is huge too [https://plus.google.com/ripples/details?activityid=TupMP3Zjq...](https://plus.google.com/ripples/details?activityid=TupMP3ZjqUg)

</comment></comment><comment><USER8> IMO, this feature should not be part of core G+ experience. It might be useful for top 1% of users to see how influential they are.

Instead, empower the App developers do such awesme innovation with your data. <yegge_repeat> Learn to think like a PLATFORM! </yegge_repeat>

<comment><USER9> "IMO, this feature should not be part of core G+ experience. It might be useful for top 1% of users to see how influential they are."

Why?

<comment><USER10> It should be part of G+, because it's cool and google usually does cool things. But it is indeed useful only for the top % of users, because the average user doesn't get that many reshares.

PS: yes, I would really love to be able to build apps/games for G+ the same way I can for Facebook. If G+ would do that I bet developers would jump on the opportunity. It's going to be like .. Android vs the iPhone all over again

</comment></comment></comment><comment><USER11> This is pretty off-topic, but is there some secret google setting that makes scrolling on a touchpad scroll instead of zooming? I'm sort of resigned to it in maps, but this thing has it too.

<comment> brown9-2 I am curious what the purpose of disabling zoom for a touchscreen device is - hard to see pictures on an iPhone you can't zoom in on.

<comment><USER12> What he means is, on a mac when you use two-finger together in a swiping motion, it'll scroll whatever document the mouse is on.

The google stuff (eg maps) has it where if you do the two-finger swiping motion, instead of scrolling, it'll zoom. Which is incredibly annoying.

</comment></comment></comment><comment><USER13> I know we talk a lot about privacy here and Google's requirement to use your real name. When seeing people's names and the network effects of events like this, it gets a bit unsettling. At least with Facebook, social networks and groups are relatively closed.

Update: Imagine the ability for a govt/group/organization to constrict the information flow by eliminating the strongest nodes in the sharing structure.

<comment><USER14> _At least with Facebook, social networks and groups are relatively closed._

I'm no Facebook expert, but I believe that Facebook also has the three ingredients necessary to do this: 1) the ability to make public posts, 2) the concept of sharing posts, and 3) attribution of who the post came from when you share it.

It's not like this Google+ visualization is about private posts. The following page clearly says it is limited to those that are public.

[http://www.google.com/support/plus/bin/answer.py?hl=en&a...](http://www.google.com/support/plus/bin/answer.py?hl=en&answer=1713320&p=about_ripples)

</comment></comment><comment><USER15> I don't know why there's so much hostility towards G+. So what if it's not the best product yet or if it doesn't have feature X that you want, they are making improvements every single week. Ripples is just another cool thing, and you can choose to either use or not use it. At least they're improving at an incredible rate and adding features that at least some people (like me) really love.

I'll repeat that you can also choose not to use it and post irrelevant negative comments on whatever favorite social network you have.

</comment><comment><USER16> Another crappy and useless feature from G+.</comment>