SPINPAL DP with Phosphor Screen http://physicstoys.blogspot.com/p/physics-toy-store.html Chaotic motion from a simple assembly of two physical pendulums (one attached to the end of the other) with the energy of the system moving frenetically back and forth between the potential energy of gravity to the kinetic energy of motion. A UV diode traces the intricate path of the pendulum on a phosphorescent screen. The chaotic motion observed here is characterized by extreme sensitivity to initial start