Stigmergic Swarm Construction

No robot in this swarm has a blueprint, a map, or knows what any other robot is doing. Instead each one senses a pheromone field left behind on the build grid by previous construction, decides whether to place a block using a response-threshold rule from real stigmergy theory, and every new block deposits more pheromone that makes the next robot more likely to build in the same place. That single feedback loop — build, deposit, sense, build again — is enough to grow discrete towers out of a flat empty grid with zero central coordination, mirroring how termites raise mounds and how modern swarm-construction robots (like MIT's TERMES) coordinate without radio communication. Adjust the colony's pickiness, the pheromone's evaporation and diffusion rates, and the swarm size to watch the site organize itself differently every run.