The illusion consists of a two dimensional figure, such as a circle or square, superimposed over a background of radial lines or concentric circles. The result is an optical illusion in which both the figure and the rectangle which contains it appear to distorted; in particular, squares appear slightly bulged, circles appear elliptical, and the containing rectangle appears tilted.
- Fineman, Mark (1996). The Nature of Visual Illusion. Dover Publications. pp. 152–153. ISBN 0486291057.
- Robinson, J.O. (1998). The Psychology of Visual Illusion. Dover Publications. pp. 72–73. ISBN 978-0486404493.
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