The Magical Mystery Chord

Beatle fans' wag of the finger. An extra note?

"The opening chord to "A Hard Day's Night" is famous because for 40 years, no one quite knew exactly what chord George Harrison was playing. Musicians, scholars and amateur guitar players alike had all come up with their own theories, but it took a Dalhousie mathematician to figure out the exact formula. Dr. Brown used Fourier transforms to find the notes in the chord, and deduced that another George — George Martin, the Beatles producer — also played on the chord, adding a piano chord that included an F note impossible to play with the other notes on the guitar."

Source: Slashdot