Two mechanical arms are mounted near one another. Each of these arms has a circular joint in the middle and a small lamp at the end. The arms are attached to motors which rotate the arm upwards and then release it, allowing it to swing like a pendulum. The momentum transferred through the circular joint causes the lower section of each arm to spin and twirl unpredictably, its movements emphasised by the lamp at the end. Identical inputs lead to two different results; these continue to play out in parallel as the swinging arms gradually come to a standstill.