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
Checker shadow illusion Checker shadow illusion The checker shadow illusion is an optical illusion published by Edward H. Adelson, Professor of Vision Science at MIT in 1995. The image depicts a checkerboard with light and dark squares, partly shadowed by another object. The optical illusion is that the area labeled A appears to be a darker color than the area labeled B. However, within the context of the two-dimensional image, they are of identical brightness, i.e., they would be printed with identical mixtures of ink, or displayed on a screen with pixels of identical colour. That the two squares are the same color