Three types of chaos. Computer models of (from top to bottom) a random wave, spinning rotators, and electron flow. The random wave is the random addition of waves, an example of quantum chaos. A simple rotator is three or more rods connected at their ends to allow them to rotate independently about these connection points. This independent rotation is an example of classical chaos. The branching lines are the tracks of electrons moving chaotically under classical laws. The colours show the angles at which they were launched. Chaos is observed when patterns emerge from complex dynamic systems with unpredictable behaviour. These models form an artwork by Professor Eric Heller.