Orbison illusion

The Orbison illusion is an optical illusion that was first described by the psychologist William Orbison (1909 – 1981) in 1939. It consists of a figure placed over a background of concentric circles or radial lines. The bounding rectangle and inner square both appear distorted in the presence of the circles or radiating lines. The background gives us the impression there is some sort of perspective. As a result, a distorted shape is seen. This is a variant of the Hering and Wundt illusions.