Electronic Labyrinth: THX-1138 4EB (1967) by George Lucas

Electronic Labyrinth: THX-1138 4EB is a short film directed by George Lucas in 1967 while he attended the University of Southern California. The movie exists in 16mm reference print, on videocassette with a run time of 15 minutes, and on the special director's edition DVD of THX 1138,,an alternate version of Lucas' 1971 directorial debut which feature's newly added scenes. This short was used as the basis for Lucas' first feature film in 1971 titled, THX-1138 and starring Robert Duvall, Maggie McOmie, and Donald Pleasence.

References: http://en.wikipedia.org/wiki/Electronic_Labyrinth:_THX_1138_4EB and http://en.wikipedia.org/wiki/THX_1138