This was a birthday card I did for my Dad as you may be to tell from the message "Happy Birthday Dad!" which is revealed in the program. It's a very simple program - you hold down the mouse button and ants come spewing out of your pointer and scuttle around randomly until they hit a "sticky" patch of the screen whereupon they stop. These sticky patches form the birthday greeting message so when there are enough ants stuck to it you can read the message. It may seem a bit weird to spell out a birthday greeting in dead insects, but that's okay: my Dad's weird too. Feel free to send it your Dad (though don't necessarily expect him to speak to you again.)
Click and drag to drop ants around the screen. Spray them liberally to reveal the message or not as you see fit.