ABSTRACT
This chapter presents some of the most common forms of visual illusions in a picture book, or catalog, fashion. It begins with illusory distortions in which the apparent size of objects is erroneously perceived when compared to what we would expect on the basis of actual physical measurements. This size distortion is subdivided into two general types. In the first, a single linear extent, such as the length of a line or the space between two figural elements, is distorted. The second type of size distortion involves the misperception of area. Many of the same principles and pattern manipulations that cause distortions of linear extent also cause distortions in area. The chapter shows a variant of the Ponzo illusion in which the circle closer to the apex of the angle is seen as uniformly larger than the circle farther back in the body of the angle.
