The Biham–Middleton–Levine traffic model is a cellular automaton that describes cars driving on a grid. The blue dots are cars that only move downwards; the red dots are cars that only move rightwards. The two types of cars take turns to move. Despite its simplicity, the model eventually forms an interesting pattern from a random starting position. When there are few cars, the traffic will always end up flowing smoothly, whereas when there are many cars, the traffic will become jammed. In this animation, there are neither too many cars nor too few cars, so it displays a mixture of jams and free flows.Animation: User:Purpy Pupple