Particle Swarm Optimisation (PSO) uses particles which ‘speak to each other’. PSO was never intended to actually solve problems, but to help us understand how societies interact and come to decisions.

Solving a Very Hard Problem
H(x) is the Heaviside Step Function
(The axes have been rescaled)

I should put tails on the little blighters.

Swarm migrates to best location.
There is always one particle at the best solution (not shown) which doesn’t move,.