Model of a Penrose staircase
1968
1968
1967
1969
1968
1967
1839 (original); circa 1988 (replica)
1967
(1962); 1982
1990-96
1903 (original); 1982 (model)
2000-100 BCE
4000-2001 BCE
1967
circa 1969
1968
1969
1967
1968
1967
1968
1969
1969
1968
1968
1969
1968
1969
1969
1968
1969
1969
1968
1969
1968
1968
1968
1969
1969
1969
1969
1968
1968
1969
1968
1969
1968
1968
1968-1969
1980-1950
1968