Wikimedia Commons
The Penrose staircase, also known as the staircase illusion, is an impossible figure based on a staircase in the form of a continuous loop that seems to rise endlessly. Each step appears to be higher than the previous one, yet anyone completing a circuit of the staircase will end at the same level as they started at. The illusion is named after the English psychologist and geneticist Lionel Penrose and his son the mathematical physicist Roger Penrose, who published a version of it in the February 1958 issue of the British Journal of Psychology.[1][2] Unknown to the Penroses, however, the impossible staircase had previously been depicted by the Swedish artist Oscar Reutersvärd (1915–2001) in 1937.[3]
In their 1958 article the Penroses noted that “each part of the structure is acceptable as representing a flight of steps but the connections are such that the picture, as a whole, is inconsistent: the steps continually descend in a clockwise direction.”[4] The Penrose staircase was the inspiration for what is generally considered to be one of the Dutch artist M. C. Escher’s most “iconic” works, Ascending and Descending, created in 1960.[5][6]
See also
- Penrose triangle
Visual representation of a triangular frame that could not exist in three-dimensional space.
