Also known as paradox. Both terms are indebted to the Greek words para (beside, near, resembling, accessory to, beyond, apart from, abnormal) and doxa (opinion, expectation). They refer to a * visual illusion mediated by objects or images that are paradoxical or logically impossible. Some well-known examples of the paradox illusion are the * motion aftereffect, the Penrose triangle, and the impossible staircases in the drawing Ascending and Descending by the Dutch graphic artist Maurits Cornelis Escher (1898-1972). The term paradox illusion is used in opposition to the terms * ambiguous illusion, * distortion illusion, and *fiction illusion.
References
Gregory, R.L. (1991). Putting illusions in their place. Perception, 20, 1-4.
Dictionary of Hallucinations. J.D. Blom. 2010.