Algodoo

This is my version of faytree's great idea. I used faytree's basic scene, but made the receptor boxes much smaller for better image resolution, and I made them stay over the image for a period of five Algodoo seconds.

How to use: Scan your cursor over the dim image of a car as if you were painting it with an airbrush. Then move the cursor far away from the image, and in about 5 seconds, the square dots will disappear.