Mark Swed: Terry Riley’s ‘In C’ “is simply a collection of 53 melodic motives, all in or around the key of C. Any instrument or vocalist — and any number of them — can play or sing. Each motive is repeated, over a pulse, as long as each performer wants before moving on. … I was told not only that I couldn’t bring that sacrilege into the classroom, but to get it out of the music building and that the only place for it on campus was the trash can. That’s when I knew the revolution had begun.”