You might have to look in the code for it to make a bit more sense. Basically, when the cat at the top of the screen detects that the space bar is pressed, it sets "my variable" to 0 and then broadcasts a message to each other cat. When each cat receives the message, it changes "my variable" by 1 and then says the value of "my variable". The purpose was to detect the order sprites receive broadcasts. Turns out it's based on the layer of the sprite. Click a sprite to send it to the front layer (which runs first). Then press space bar again to see the run order.
