5-Shuttle Trammel of Archimedes: As the shuttles take turns completing their straight line journeys, the end of the crank arm traces an ellipse- and each of the five shuttle points define points on a smaller circle that rolls within the perimeter of the device. Featured also in this video- a nice version of the standard 2-shuttle version. Sometimes sold as a “do nothing machine” or “nothing grinder”, far from doing nothing this simple and crucially important mechanism demonstrates how rotational