Bruce included a description of the routine in his Castle Notebooks, dated 8/24/67 (this is volume 4 of the L&L books). His annotation is "See Famous Larry Jennings Chop Cup Routine Genii This is really Ron Wilson's -- This is a very very fine routine." Note that there are minor differences in the published versions. I used to do the routine as published in Genii, and then, when I moved to the Magic Castle, I saw Ron Wilson do it and he fooled me badly. He also had the great idea to do it with a cardboard coffee cup from Coffee Dan's, which got a laugh and seemed so innocent.