Particles with “spatial memory” exhibit mesmerizing patterns in their movements.

In the mathematical version of billiards, particles that avoid following paths become trapped in complex and difficult-to-predict patterns. This may ultimately help us understand complex movement patterns in organisms.

Animals such as ants and slime molds leave traces of chemicals in the environment as they search for food, which can prevent them from accidentally retracing their tracks. Although this behavior is not uncommon in biology, Majyar Jalal A professor at the University of Amsterdam in the Netherlands and his colleagues…