Kinetic Depth Effect
The phenomenon whereby the three-dimensional structural form of an object can be perceived when the object is moving, such as a rotating wire shape cast onto a screen.
Origin
American perceptual psychologist Hans Wallach and his collaborator D.N. O'Connell named and described the effect in a 1953 paper that became one of the most widely cited studies in perceptual psychology. Their experiments used rotating wire-frame shapes projected as shadows onto a translucent screen: static, the shadows appeared flat; once the object rotated, observers perceived vivid three-dimensional form. Wallach, who had fled Nazi Germany in 1941 to join Swarthmore College, spent decades studying how the visual system recovers depth and structure from motion — of which the kinetic depth effect became the definitive demonstration.