- Abstract Physical A*(PHA*) and its multi-agent version MAPHA*[3, 4] are algorithm that find the shortest path between two points in an unknown real physical environment with one or many mobile agents. Previous work assumed a complete sharing of knowledge between agents. Here we apply this algorithm to a more restricted model of communication which we call large pheromones, where agents communicate by writing and reading data at nodes of the graph that constitutes their environment. Unlike small pheromones where only a limited amount of data can be written at each node, the large pheromones model assumes no limitation on the size of the pheromones and thus each agent can write its entire knowledge at a node. We show that with this model of communication the behavior of a multi-agent system is almost as good as with complete knowledge sharing.