Optimal trajectories (solid line) for different starting positions around a semicircle towards three targets (open circles). The two targets on the right are shown slightly apart but are in fact coincident; the dashed line separates the zones of attraction of the two target positions. The inner ring of numbers gives the probability of reaching each of the two coincident targets. The mean rate of disappearance of each target is 0.1 per time taken to move a unit distance, where the target positions are 1 unit apart.