“I’m Only Sleeping” has that backwards guitar solo.

“I’m Only Sleeping” — and it happened because someone hit rewind by accident.

George Harrison recorded the guitar solo. During a playback session, engineer Geoff Emerick accidentally played the tape backwards. Everyone in the room liked how it sounded. So they kept it.

That’s the version you hear on Revolver. No one was trying to be psychedelic or experimental. Just a happy mistake, one of dozens the Beatles stumbled into because they were always messing with tape.

Tape accidents like this are why the Beatles sounded like no one else.