Notes for "How to Lingo," Part 3

Here are some notes and hints you may find useful in working on Part 3 of the "How to Lingo" project.

• The number of the frame on which the playback head rests at any given moment (that is, on any given execution of an enterFrame handler) is contained in a variable called the frame.
  
  
• The Lingo expression X mod(2) evaluates to zero when X is an even number and to one when X is an odd number.
  
  
• To make a sprite invisible, set its visible property to false; set that property back to true to make the sprite visible again.
  
  
• To set the property of a sprite, refer to the sprite by its channel number. So the expression sprite(2).visible=false turns the sprite in channel 2 invisible.
  
  
• In Director, a channel closer to the bottom of the score (the bottom of the screen) corresponds to a visible layer on the stage that is apparently closer to the viewer. So "low" in the score corresponds to "high" or "outside" on the stage. Thus a sprite in channel 4 sits on top of a sprite in channel 3.
  
  
• You'll probably want to attach a script to at least one of the Cast Members that contain your butterfly graphics.