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
Crater illusion image of Mercury's Spitteler and Holberg craters taken by the MESSENGER spacecraft. The image on the left is the original image and the image on the right is the same image rotated in an attempt to remove the illusion. In the image on the left of the Tin Bider crater produced by NASA Earth Observatory's EO-1-based Advanced Land Imager produces a reverse illusion. The crater rises above the surrounding terrain, however the position of the sun makes it appear to be below it. Crater illusion The Crater Illusion also known as the Crater/Dome Illusion or Dome Illusion is an optical