This looks cool...Thomas Pavitte has reinvented the paint-by-numbers with Querkles. Instead of simple numbered areas to fill in, Querkles cleverly uses overlapping circles that you fill in with different shading techniques or colors to reveal hidden faces. Here's a short demo of how it works:
Pavitte has two different books available: Querkles and Querkles Masterpiece, featuring famous faces from the art world. See also coloring books for adults.
Thomas Pavitte designed and then solved the world's largest connect-the-dots puzzle (of the Mona Lisa). It took him 9 and 1/2 hours.
A time lapse video of Pavitte solving the puzzle is up on Vimeo. (via colossal)