A double pendulum made of anodised aluminium for mounting on a rigid wall. Both lengths of the pendulum are manufactured with the utmost precision and rotate, or oscillate, without friction around their pivots. The way the movement develops is unpredictable and therefore chaotic.
Depending on the initial conditions, the pendulum lengths begin rotate and lose energy due to friction. Once the energy is no longer sufficient, the rotation gives way to oscillation. The motion of each of the pendulums is affected by the other. This means that the rotation of the second length can be transferred to the first, which may provide it with enough energy to rotate again. The chaotic pendulum stops when all the energy has been lost due to friction.