An impossible figure based on a staircase in the form of a continuous loop that apparently rises endlessly (see illustration), first devised in 1958 by the English psychologist/geneticist Lionel S. Penrose (1898–1972) and his mathematical physicist son Roger Penrose (born 1931), later incorporated into Ascending and Descending, one of the best known etchings of the Dutch graphic artist Maurits C(ornelis) Escher (1898–1970). Also called the Penrose staircase. Often confused with the Schröder staircase. See also auditory staircase illusion.
Staircase illusion. An impossible figure in which a flight of stairs appears to rise endlessly.