Ant colony

Open world: a wall between the nest and the food, with two ways around it (slow mud above, fast below). Two pheromones (to-food and to-home), each ant smells only its own. The colony converges on the fast route by itself, with nobody computing it.

Brush

Brush size

Parameters

Ant count 300 Evaporation (food trail) 0.997 Diffusion 0.10

Legend

trail to food (green)

trail to home (blue)

ant exploring

ant carrying food

Why is it emergent?

No ant knows the map. Each one smells only one pheromone (explorers the to-food one, carriers the to-home one) and heads where it smells the most; the wall blocks smell, so nothing can be smelled through it. The fast route gets traveled more times per minute, receives more pheromone before it evaporates and gets reinforced; the slow one fades away. Nobody decides the optimal route: it arises from the sum of local decisions.