I don't believe that Woody put the examples together as a teaching aid for his assistants, but rather as a reminder to himself. He was always trying to kick himself to put less labor into the work! He had a framed motto on the wall, "Never draw anything you can copy, never copy anything you can trace, never trace anything you can cut out and paste up." He hung the sheets with the panels on the wall of his studio to constantly remind himself to stop what he called "noodling."

http://joeljohnson.com/archives/2006/08/wally_woods_22.html