Syd Barrett (6 January 1946 – 7 July 2006), born Roger Keith Barrett, was a founding member of band Pink Floyd. He left the group in 1968 amidst speculations of mental illness exacerbated by heavy drug use. Through late 1967 and early 1968, Barrett's behaviour became increasingly erratic and unpredictable, partly as a consequence of his reported heavy use of psychedelic drugs, notably LSD.
There are many stories about Barrett's bizarre and intermittently psychotic behavior, some known to be true. According to Roger Waters, Barrett came into what was to be their last practice session with a new song he had dubbed "Have You Got It, Yet?". The song seemed simple enough when he first presented it to his bandmates, but it soon became impossibly difficult to learn and they eventually realized that while they were practicing it, Barrett kept changing the arrangement. He would then play it again, with the arbitrary changes, and sing "Have you got it yet?". Eventually they realized they never would and that they were simply bearing the brunt of Barrett's idiosyncratic sense of humor.
Pink Floyd (Syd Barrett) - See Emily Play