Kinetic art expressions based on optical and luminous phenomenon as well as painting illusionism. The expression "kinetic art" in this modern form first appeared at the Museum für Gestaltung of Zürich in 1960, and found its major developments in the 1960s. In most European countries, it generally included the form of optical art that mainly makes use of optical illusions, such as op art, represented by Bridget Riley, as well as art based on movement represented by Yacov Agam, Carlos Cruz-Diez, Jesús Rafael Soto, Gregorio Vardanega, or Nicolas Schöffer. From 1961 to 1968, GRAV ("Groupe de Recherche d’Art Visuel") founded by François
Cornsweet illusion generate percepts on an empirical basis that is much like a reflex. In their words, "... [perception] accords not with the features of the retinal stimulus or the properties of the underlying objects, but with what the same or similar stimuli have typically signified in the past." Cornsweet illusion The Cornsweet illusion, also known as the "Craik–O'Brien–Cornsweet illusion" and the "Craik–Cornsweet illusion", is an optical illusion that was described in detail by Tom Cornsweet in the late 1960s. Craik and O'Brien had made earlier observations in a similar vein. In the image at right, the entire region to the right