The Penrose Triangle
The Penrose triangle, also known as the Penrose tribar, is an impossible object. It was first created by the Swedish artist Oscar Reutersvärd in 1934. The mathematician Roger Penrose independently devised and popularised it in the 1950s, describing it as “impossibility in its purest form”.
Above: Each of the black shapes above are variations of the Penrose triangle, and all of them are a little bit impossible in some way… Source.