Four Sided Triangle is a 1953 British science-fiction film directed by Terence Fisher, adapted from a novel by William F. Temple. It starred Stephen Murray, Barbara Payton and James Hayter. It was produced by Hammer Film Productions at Bray Studios.The film dealt with the moral and scientific themes (not to mention "mad lab" scenes) that were soon to put Hammer Films on the map with the same director's The Curse of Frankenstein.