The Penrose stairs or Penrose steps, also dubbed the impossible staircase, is an impossible object created by Lionel Penrose and his son Roger Penrose. Bedankt Ivan de Winne![br][br][br]

An impossible figure in which a stairway in the shape of a square appears to circulate indefinitely while still possessing normal steps (Penrose and Penrose 1958). [br]The Dutch artist M. C. Escher included a Penrose stairway in his mind-bending illustration "Ascending and Descending"