anchor.diff:  To trigger a cue, simply press the corresponding pad on a physical
   interface, or click within the grid cell in the web interface. The
   effect associated with the cue will be created and added to the show,
  -and the grid cell will be lightened to indicate that the cue's
  +and the grid cell will be lightened to indicate that the cue&rsquo;s
   effect is running. If the cue ends itself after a period, the grid
   interface will be updated to reflect that as well.
   
  -To end a cue's effect before it would naturally end (or because
  +To end a cue&rsquo;s effect before it would naturally end (or because
   it is open-ended and does not end until asked to), simply press the
   pad corresponding to the running cue (or, again, click the grid cell
   in the web interface). The effect will be asked to end. Some effects
  
positive.code: 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'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
  
negative.code: bottom left corner is assigned coordinates `(0, 0)`. X coordinates
  increase from left to right, and Y coordinates increase from bottom to
  top. The web interface and registered grid controllers display 64 cues
  at a time in an 8&times;8 grid, and can be scrolled around that grid.
  The user can set the web interface to track the scroll position of a
  registered grid controller. When that is done, scrolling either
  interface will cause the other to scroll in the same way, so the
  browser window can act as documentation to help the user learn the cue
  names associated with each available cue pad on the controller.
  
  image::assets/ShowGrid.png[Web interface]
  
  