Performing an algorithmic image analysis of the Where's Waldo books might be a lot of fun. It'd be nice to see what the largest area / pattern that the author re-used when drawing Waldo is. Probably it's the area between the top of his glasses and his chin... anyone know of a good tool for this type of thing? Maybe Amazon's Turk?
From SA's "Woman Disappears; clip-art truck may have been involved" thread: