anchor.diff:  |The offset along the fixture Z axis, in meters, from the geometric
    center of the fixture (the point at which Afterglow is told the
    fixture is located when patching the fixture) and the geometric
  - center of this head. If this head is centered within the fixture X
  + center of this head. If this head is centered along the fixture X
    axis, you can omit this value or you can supply it with a value of
    0.0. The <<show_space#show-space,Show Space>> page illustrates the
    axes and links to a function you can use for converting inches to
  
positive.code: |Key
  |Purpose
  
  |:name
  
  |A string which identifies the manufacturer and model of fixture.
  
  |:channels
  
  | A list of channel specifications which tell Afterglow about the DMX
  
negative.code: probably need to create your own. You can study the existing fixture
  definitions for examples of how it is done. You can also ask for help
  on the https://github.com/brunchboy/afterglow/wiki/Questions[wiki].
  
  TIP: When you first embark on the project of creating a fixture
  definition, it might seem overwhelming. This page is long, and
  includes a great deal of complicated detail. But don't despair! First,
  remember that most fixtures only do a subset of the kinds of things
  that the fixture definition mechanism needs to handle, so you do not
  need to learn and understand all of it at once. And even more helpful
  to beginners, realize that you do not need to finish your fixture
  definition before you can start using and testing it. Your fixture may
  be capable of many things, but start out by defining just a couple of
  channels that will make it at least light up, and see if you can get
  those working in a show. Once they are, you can already use the
  fixture at least at that level. And that success can be a foundation
  for digging deeper into other types of channels, which you can add to
  your definition one at a time, building on what you learn as you go
  along.
  
  The namespace
  http://deepsymmetry.org/afterglow/doc/afterglow.fixtures.html[afterglow.fixtures]
  