Back in 1970, in my first semester in Art school at the University of Denver, I took a drawing class with the San Francisco artist Ken MacDonald. He was a hardcore hippie.
For the very first class he put this piece on the record player and instructed us to draw, paint, whatever: a recent dream we might have had.
It was quite something, really; and I ran out after class to buy the album and became a Terry Riley fan ever since. This excerpt is from the Hall of Mirrors at Versailles.