Flash drawing with students

I was using my self-portrait in class today for a Flash drawing demo (see technique here). When I stepped away for a bit, one of my teaching assistants sat down and began adding to the drawing, followed by another one of my assistants who added some line work of her own. I finished it up the drawing later and above are the results. The top row, left to right, is Mikey's, Francesca's, and then both of theirs together. The bottom row, left to right, is my contribution, all of the line work, and with onion skin activated to reveal the underlying sketch.