Optical Illusion Keychain

Instructions: 1) focus gaze on red dot 2) wait for disc to hover and wiggle over the background design 3) be amazed! (it helps if you clicky on the magnifying glass button there to view the product full-size). We're guessing the effect results from the differing characteristic spatial frequencies of the foreground and background that generate error signals during micro-saccades that the brain cannot cancel simultaneously. Science!