The Impossible Cube is an optical illusion that appears to be a three-dimensional cube, but is actually a two-dimensional image. It is a paradoxical shape that defies logic and challenges the viewer to try to comprehend it. The Impossible Cube is a fascinating visual puzzle that will leave
From Wikipedia
The impossible cube or irrational cube is an impossible object invented by M.C. Escher for his 1958 print Belvedere. It is a two-dimensional figure that superficially resembles a perspective drawing of a three-dimensional cube, with its features drawn inconsistently from the way they would appear in an actual cube.