anchor.diff:  lets you drag an aiming point around a map of the stage is one fun
   possibility.
   
  -# Function Effects
  +== Function Effects
   
   Fixtures have a wide variety of different capabilities, often more
   than would be reasonable to assign a separate DMX channel for each,
  
positive.code: effects to a fixture to make sure you also have a dimmer effect setting
  that fixture’s dimmer to some visible level.
  
  ## Direction Effects
  
  Moving-head fixtures can create particularly exciting and dynamic shows.
  To create an effect that will tell a fixture or head what direction it
  
negative.code: <<parameters#oscillated-parameters,oscillated parameters>> can
  create fascinating motions.
  
  == Aim Effects
  
  These are very similar to <<direction-effects,direction effects>>,
  except they tell each fixture to aim at a particular point in space,
  