The Penrose triangle, also known as the "impossible triangle," is an optical illusion that creates the appearance of a three-dimensional object made from straight beams. It was first created by the mathematician Roger Penrose in the 1950s and is often used in art and design to challenge perceptions of reality. The triangle cannot exist in three-dimensional space, as its structure defies the laws of geometry. This intriguing shape is often featured in works by artists like M.C. Escher, who is known for his mind-bending illustrations. The Penrose triangle serves as a fascinating example of how visual perception can be manipulated, leading viewers to question the nature of reality and dimensionality.