Ryoko found a beautiful Japanese tool for scoring cardboard here http://www.pen-info.jp/orita.html, and it inspired us to make our own version with a bicycle gear. I consulted with Ray G, the Exploratorium’s resident bicyclephile and talented gearhead. He came up with this great design. It uses a BMX freewheel and works beautifully! Luigi was the first one to try it out, and voila! Cardboard origami.