Op art

Op art, also known as optical art, is used to describe some paintings and other works of art which use optical illusions. Op art is also referred to as geometric abstraction and hard-edge abstraction, although the preferred term for it is perceptual abstraction. The similar sounding Pop art and Plop art are art terms unrelated to Op art.

"Optical Art is a method of painting concerning the interaction between illusion and picture plane, between understanding and seeing." Op art works are abstract, with many of the better known pieces made in only black and white. When the viewer looks at them, the impression is given of movement, hidden images, flashing and vibration, patterns, or alternatively, of swelling or warping.