Model of a Penrose staircase
1968
1968
1967
1969
1968
1967
1839 (original); circa 1988 (replica)
1966
1967
(1962); 1982
1966
1966
1966
1903 (original); 1982 (model)
2000-100 BCE
4000-2001 BCE
1967
circa 1969
1969
circa 1966
1968
1967
1968
1967
1968
1969
1966
1969
1968
1969
1968
1968
1969
1969
1968
1969
1969
1968
1969
1969
1968
1969
1968
1968
1969
1969
1968
1968
1969
1969
1968