Boids — Emergent Flocking

Reynolds' Boids (1987) demonstrates that complex flocking, schooling, and herding behavior emerges from three simple local rules: Separation — steer away from nearby neighbors to avoid crowding; Alignment — steer toward the average heading of neighbors; Cohesion — steer toward the average position of neighbors. No individual boid knows the global state — the flock is fully emergent. This was among the first convincing demonstrations of emergence in artificial life.