anchor.diff:  |The offset along the fixture X 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: 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].
  
  The namespace
  http://deepsymmetry.org/afterglow/doc/afterglow.fixtures.html[afterglow.fixtures]
  
negative.code: |Key
  |Purpose
  
  |:channels
  
  | A list of channel specifications which tell Afterglow about the DMX
  