Op art is a style of painting which makes use of optical illusions and other kinds of unusual optical effects. Victor Vasarely a Hungarian artist, was perhaps the first to use this theme regularly, in the 1930s. In the 1960s, Bridget Riley became one of the world's best-known op artists. She specialised in the effects produced by closely fitted lines. Jesús Rafael Soto used mobile elements, so connecting op art with kinetic (moving) structures.