anchor.diff:  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 this view can be scrolled around
  -within the larger grid. The user can configure ("`link`")
  -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.
  +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]
   
  
positive.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.
  
  
negative.code: by the cue can be updated by the aftertouch pressure exerted by the
  operator as they hold down the pad. This can make for very expressive
  effects, as exemplified by the Sparkle cue set up early in the
  examples namespace&rsquo;s
  http://deepsymmetry.org/afterglow/doc/afterglow.examples.html#var-make-cues[make-cues]
  function, and its
  http://deepsymmetry.org/afterglow/doc/afterglow.examples.html#var-make-strobe-cue[strobe]
  