Listen, play, love, revere – and keep your trap shut!" Albert Einstein's words on Bach might equally apply to Robert Wilson and Philip Glass's Einstein on the Beach, which, along with glancing references to Carole King, The Beatles and "Mr Bojangles", is threaded through with shreds of Bach's E major Partita as played by a man with a shock of white hair, a bushy moustache, and the pink, protruding tongue of a happy Labrador.