anchor.diff:  http://deepsymmetry.org/afterglow/doc/afterglow.effects.cues.html#var-cue[cue]
   function creates a cue. At its most basic, you pass in two parameters,
   `show-key` which is the keyword that will be used to add the
  -cue&rsquo;s effect to the show when the cue is triggered, ending any
  +cue's effect to the show when the cue is triggered, ending any
   other effect running under that same keyword, and `effect`, which is a
   function that will be called when the cue is triggered, and whose
   responsibility is to create and return the effect that the cue should
  
positive.code: the web interface is the most practical way of scrolling them.)
  
  Cues can also be triggered from simpler MIDI controllers (which
  don&rsquo;t register as grid controllers) by explicitly mapping notes
  or control changes sent by the controller to cues within the grid
  using
  http://deepsymmetry.org/afterglow/doc/afterglow.show.html#var-add-midi-control-to-cue-mapping[afterglow.show/add-midi-control-to-cue-mapping].
  
negative.code: 
  |Sets the text to be displayed for the cue in the web cue grid, and in
  the text display of the controller (if it has one) when the cue is
  running. If you don't supply a short name, the name of the
  effect created by the `effect` function is used, but that may be too
  long or not informative enough.
  
  