Optical Illusions

The so called Pacman illusion. This shows two phenomena, negative color space and image persistence. 12 or so purple dots one by one blink off. That is all the video shows. When looking at the cross in the center, the absense of a purple dot appears as a green dot. After 1 or 2 rotations, while holding your vision on the cross, the purple dots begin dissapearing, until you see only a single rotating green dot. Once you scan your eyes around the scene, the illusion breaks, and all you see is a ring of purple dots with a moving blank spot.