In this problem a series of drones tries to find a path from the source
to the target while staying away from the obstacles. They use pheromones.
I tried to implement something similar to
H. Van Dyke Parunak, Sven Brueckner, and John Sauter. Synthetic pheronome mechanisms for coordination of unmanned vehicles In Proceedings of the First Intenational Joint Conference on Autonomous Agents and Multiagent Systems, pages 448-450, Bologna, Italy, 2002. ACM Press, New York, NY.