Four Sided Triangle

In this early Hammer sci-fi offering, two childhood friends develop a machine that can replicate anything, leading to a tangled web of love and duplicity. When "Robin" marries their childhood friend "Lena", his co-developer "Bill" creates an identical version of himself named "Helen", but things take a complicated turn when Helen falls in love with Robin too. With disastrous consequences, Bill tries to erase Helen's knowledge of Robin using electric shock therapy, leading to a fire that destroys both him and the duplicate woman he created, leaving Lena alive and wondering who she rescued from the inferno.