Attendees extend the 'sign of the horns' hand symbol during a heavy metal concert at the Wacken ... it so much that it became the symbol of rock 'n' roll of some kind." So then, who started ...

With a rebellious rock 'n' roll spirit ... since his fretting hand got chopped due to an industrial accident, but then again, maybe metal wouldn't sound the way it does if Iommi had a full ...

Index finger up, middle fingers down, pinky up, thumb in: the standard rock 'n' roll salute ... that he took the hand sign ...