The Penrose Triangle, also known as the Tribar, is an impossible object first created by Swedish artist Oscar Reutersvärd in 1934. The mathematician Roger Penrose, who gave the object its name, independently developed and popularised this figure in the 1950s. This figure appears particularly frequently in the artworks of M.C. Escher.


From a certain perspective, the tribar appears to be a solid object consisting of three straight beams. The straight beams appear to form a regular triangle with one right angle and two 45 degree angles. This optical illusion can be represented in two or three dimensions. In a three-dimensional sculpture, the representation is only possible in that the lower and right sides of the triangle only appear to meet, but are actually far apart. Viewed from a certain direction, the figure looks like a complete triangle.