2. Op art, also known as optical art, is a style of visual art that makes use of optical illusions.

3. 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 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.

6. First and foremost, Op Art exists to fool the eye. Op compositions create a sort of visual tension, in the viewer's mind, that gives works the illusion of movement. For example, concentrate on Bridget Riley's Dominance Portfolio, Blue (1977) - for even a few seconds - and it begins to dance and wave in front of one's eyes. Realistically, you know any Op Art piece is flat, static and two- dimensional. Your eye, however, begins sending your brain the message that what it's seeing has begun to oscillate, flicker, throb and any other verb one can employ to mean: "Yikes! This painting is moving!". Because of its geometrically-based nature, Op Art is, almost without exception, non-representational. The elements employed (color, line and shape) are carefully chosen to achieve maximum effect. The critical techniques used in Op Art are perspective and careful juxtaposition of color (whether chromatic [identifiable hues] or achromatic [black, white or gray]). In Op Art, as in perhaps no other artistic school, positive and negative spaces in a composition are of equal importance. Op Art could not be created without both.

21. Look at the following image for 30 seconds. Do not blink! Then, quickly look at the white screen. What happens?