Rollovers

There are many possible rollover effects and actions. Here is a simple one that introduces two new mouse event handlers and a command that changes the ink effect of a sprite on rollover.
on mouseWithin me
set the ink of sprite(3) = 33
end
on mouseLeave
set the ink of sprite(3) = 8
end

Ink effects are called by numbers in Lingo. They are:

0-copy
1-transparent
2-reverse
3-ghost
4-not copy
5-not transparent
6-not reverse-
7-not ghost
8-matte
9-mask
32-blend
33-add pin
34-add
35-subtract
36-background transparent
37-lightest
38-subtract
39-darkest
40-lighten
41-darken