anchor.diff:  channel specification that does not need a `:fine-offset` value).
   
   |:type
  -
   |Tells afterglow the kind of channel this is. Special values include
    `:color` for a channel that contains a color intensity, `:dimmer` for
    controlling brightness independent of color, and `:pan` and `:tilt`
  
positive.code: channels.
  
  |:functions
  
  |A list of <<function-specifications,Function Specifications>> which
   identify ranges of DMX values that can be sent to the channel, and
   which perform particular functions. Fixture manufacturers often use a
  
negative.code: |Purpose
  
  |:channels
  | A list of channel specifications which tell Afterglow about the DMX
  channels that this individual head responds to. These have exactly the
  same structure as the channel specifications for the main fixture, as
  