Lionel Penrose

Lionel Penrose (11 June 1898, London — 12 May 1972, London) was a British psychiatrist, geneticist, pediatrician, math/chess theorist, and Professor Emeritus of Human Genetics at University College London. Lionel is the son James Doyle Penrose (1862—1932) and brother of Roland Penrose (1900—1984), both painters, and the father of mathematician Roger Penrose (b. 1931), with whom Lionel co-authored papers on the Penrose triangle in the 1950s.