Roget's Palisade
Roget's Palisade
Roget's palisade is an optical illusion occurring when a spoked object travels behind a picket fence or palisade. The spokes appear distorted, curving upwards or downwards depending on the direction of movement (it is easiest to see this when staring at the center of the wheel). The distortion is caused by the afterimage of the visible parts of the wheel, which our perception joins into continuous arcs.