Four Sided Triangle is a 1953 British second feature ('B') science-fiction film directed by Terence Fisher. It was written by Paul Tabori and Fisher, adapted from the 1949 novel by William F. Temple. It stars Stephen Murray, Barbara Payton, John Van Eyssen and James Hayter. It was produced by Hammer Film Productions at Bray Studios from August to September, 1952, and foreshadowed Hammer's later entrance into horror and science fiction. The story concerns two scientists who invent a replication machine and duplicate a woman. J. Elder Wills was the art director. It was at this time that James Carreras announced that future Hammer films would be produced by either his son Michael Carreras or Anthony Hinds on a rotating basis, resulting in almost continuous filming.