Colors! developers page
Colors is a simple natural media painting activity for the XO laptop, based on a Nintendo DS program by Jens Andersson.
Rather than constructing images from geometric shapes, the user is encouraged to keep painting on their work until it looks right, starting with rough strokes and then adding extra details.
The activity features soft brushes, collaborative painting, the ability to watch tutorial paintings as they are painted, and a variety of input methods including "video paint" using the webcam.