Billy was just monkeying around on a guitar and started playing it like an upright bass. He said, “People should play guitar like this!” Well, people do, particularly the eccentric great Scottish guitarist Paul Galbraith.
He developed this 8-string guitar, I believe in order to play Bach better. He made a deep transcription and recording of the solo violin sonatas and partitas – the famous chaconne is particularly good. He has a whole crazy probably true theory about the sonatas and partitas, something about how they encode all of Christianity in them.