“People always ask who the porpoise is in the lyrics,” Ann said. The porpoise she was referring to is in the song’s bridge: “‘Sell me, sell you,’ the porpoise said / Dive down deep now to save my head ...

Part of the magic of John Lennon and Paul McCartney’s songwriting partnership was their ability to blend the former’s avant-garde experimentation with the latter’s commercial sensibilities, and few ...