Copper rods “swarm” like fish

“Swarming” is often seen in the animal kingdom, for example when
schools of fish rapidly change direction to evade a predator. Now
physicists in India and the US have made collections of tiny copper
rods swarm by vibrating them between two plates. The researchers claim
that their experiment shows how simple small-scale interactions can
give rise to large-scale changes in behaviour and could provide a
better understanding of swarming in living organisms (Science 317 105).
Copper rods “swarm” like fish (July 2007) – News – PhysicsWeb

Copper rods “swarm” like fish