Ouchi Illusion

The Ouchi illusion, named for Japanese graphic artist Hajime Ouchi who published it in 1973, is a visual illusion in which a checkered background made of rectangles at one orientation surrounds a circular patch of rectangles at a right angle to it, creating a strong impression that the central disk floats above or moves independently of the surrounding pattern. The apparent relative motion becomes most vivid when the image itself is moved slightly, such as during small eye movements, or when the whole figure is shifted from side to side. Researchers attribute the effect to how overlapping regions of the retina's receptive fields respond differently to the two orientations of rectangles, so the two regions appear to slip out of alignment with each other.