The music of Karlheinz Stockhausen, 73 year old experimental composer, has long incorporated elements of theater and spectacle. He has followed Duchampian aesthetics, searching for metaphorically violent ways of thrusting image and sound together.

His 1994 "Helicopter Quartet" (based on a dream he had of "towers of television screens", thousands of outdoor spectators, musicians in flying helicopters), was creepily prescient of September 11th as live spectacle.

Inevitably, he responded to the attack in those terms, as "The greatest work of art there's ever been. That people rehearse like crazy for ten years, totally fanatically for one concert, and then die! Compared to this, we are nothing as composers."