One of the most prominent artistic characteristics of optical illusions is their use of vibrating, contrasting and supplementary colors to create the psychological effect of illusion. Vibrating colors are created when multiple colors, that are extremely intense and saturated, are placed next to each other and appear to vibrate. Contrasting colors, or complementary colors, are those that are on opposite sides of the color wheel; for example, yellow and purple. Optical illusions most often use one of these color theories, if not both, to help them achieve the intended illusion.
The figure/ground relationship directly refers to the relationship between the figure, which is the main focus of the piece, and the background, or everything else besides the figure. At any moment the clear distinction between the figure and the ground can be blurred and almost completely disappear. This is exactly what some optical illusions try to exploit. They intentionally blur the distinction in order to achieve their desired illusion.
Highlights and shadows are used in just about every form of art to give the subject matter three-dimensionality, depth and substance. The extreme use of shadow with an accented highlight can give a two-dimensional drawing or image the feeling of being three-dimensional. Shadows and highlights have been essential to the techniques of art since its conception. Optical illusions manipulate and incorporate shadow and highlight in such a way that deceives the viewer into see something that is not really there.
Shape and line are two of the most basic fundamental aspects of art, yet optical illusions incorporate them in such a way that skews the viewer's perception of what they are seeing. With the bend of a line in a certain direction and the alteration of a shape in another direction, an optical illusion has already been created. The most basic optical illusions utilize this concept to give the appearance of lines moving, or shapes bending in seemingly implausible ways.