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
Fraser spiral illusion Fraser spiral illusion The Fraser spiral illusion is an optical illusion that was first described by the British psychologist Sir James Fraser (1863 – 1936) in 1908. The illusion is also known as the false spiral, or by its original name, the twisted cord illusion. The overlapping black arc segments appear to form a spiral; however, the arcs are a series of concentric circles. The visual distortion is produced by combining a regular line pattern (the circles) with misaligned parts (the differently colored strands). Zöllner's illusion and the café wall illusion are based on a similar principle, like many other