Early in 1970, Pink Floyd performed at gigs a piece from their film soundtrack for Michelangelo Antonioni's film "Zabriskie Point" referred to as "The Violent Sequence". This was the musical basis for "Us and Them", from their "The Dark Side of the Moon" album. Lacking only the lyrics, it is identical to the final song and is the earliest part of the seminal album to have been performed live. The song "Embryo" was also a part of the live repertoire around this time, but was never to appear on a studio album, until the compilation album "Works".