One day designer Philippe Malouin was sitting on a chair with casters when he rolled over a patch of dust, leaving tracks behind him. He was instantly inspired and set out to create a piece of furniture that would track its user’s behavior. The Ballpoint Stool is the result, a transparent stool whose legs contain ink. As you move your patterns are traced enabling you to keep track of your movements or to draw in a whole new ways. See more here.
This is so cool! What a unique idea.