An impossible object is a kind of optical illusion. It consists of a two-dimensional object that our eyes interpret as a projection of an impossible three-dimensional object. The impossible nature of these objects is noticeable after a few seconds of viewing each figure, confusing and unsettling the mind.
The Impossible Cube was invented by M. C. Escher, a famous Dutch graphic artist, for his lithograph Belvedere, in
which the rest of the scene is based on the same principle as the impossible cube.
While it was first created by Swedish artist Oscar Reutersvärd in 1934, the Penrose Triangle was independently
devised and popularised by Roger Penrose in the 1950s.
The Penrose Steps were introduced by two mathematicians, Lionel Penrose and his son Roger Penrose, in 1959. It depicts a continuous loop of ascending or descending steps.
The Blivet, also known as the Devil’s fork, appears to have three cylindrical prongs at one end, which curiously turn into two rectangular prongs at the other end.