>>35325028But he did...
"Barrett's unpredictable behaviour at the time and idiosyncratic sense of humour combined to create a song that, initially, seemed like an ordinary Barrett tune. However, as soon as the others attempted to join in and learn the song, Barrett changed the melodies and structure, making it impossible for the others to follow, while singing the chorus "Have You Got It Yet?" and having the rest of the band answer "No, no!". This would be his last attempt to write material for Pink Floyd before leaving the band. In fact, Waters stated, in an interview for The Pink Floyd and Syd Barrett Story, that upon realizing Barrett was deliberately making the tune impossible to learn, he put down his bass guitar, left the room, and never attempted to play with Barrett again. Waters had called it "a real act of mad genius". The song was never recorded by Pink Floyd or Barrett."