anchor.diff:  
   If your function does not fit into this list, make up a keyword that
   makes sense for it, following the style shown here. And also please
  -consider opening an
  +consider (if the function type is likely to be present on other
  +fixtures and useful to other people) opening an
   https://github.com/brunchboy/afterglow/issues[issue] requesting that
   your new function type be added to this list so that when other people
   create definitions for similar fixtures, they can interoperate with
  
positive.code:  interpreted as an approximate Hz rate for the strobe, and your new
   fixture will strobe in rough tandem with other fixtures being
   strobed. Take a look at the strobe function definitions for the
   existing fixtures for examples how to do this:
  
  [source,clojure]
  ----
  (chan/functions :strobe 7 0 nil
                  11 {:type :strobe
                      :scale-fn (partial function-value-scaler 0.66 25)
                      :label "Strobe (0.66Hz->25Hz)"
                      :range :variable})
  ----
  
  |:focus
  
  |Adjusts the focal plane of the fixture, usually a moving-head spot
  
negative.code:  channel <<channel-creation-functions,creation function>> to create
   the channel. Color channels are fundamental channel types in
   Afterglow, and the colors `:red`, `:green`, `:blue`, and `:white`
   will automatically participate in the color mixing Afterglow performs
   with <<effects#color-effects,Color Effects>>. The others can too if,
   as described <<hue-mixing,above>>, the `:color` channel has a `:hue`
   entry.
  
  |:pan
  