This is the 2D companion to the 3D Ant Colony Pheromone Trails simulation: the same stigmergic algorithm, viewed from directly above as a live pheromone concentration field instead of a rendered diorama. A grid of cells covering the whole field tracks two pheromone quantities — one trail marking the way to food, one marking the way home — which every ant deposits as it moves and which decay exponentially over time. Ants searching for food steer probabilistically toward the strongest nearby "to food" scent; ants carrying food steer toward the strongest "to home" scent. No ant ever measures or compares distances directly, yet because a short round trip reinforces its trail more often per second than a long one, the colony's traffic reliably converges onto a near-shortest path between the nest and each food source. Add or remove food sources with a click to watch the colony re-route in real time.