So it's basically A* with higher scores when going towards gravity, very cool. Another physics problem analogue I really like is the problem of fastest travel

So it's basically A* with higher scores when going towards gravity, very cool. Another physics problem analogue I really like is the problem of fastest travel from point A to point B when you have to cross a river. One approach to solve is is to treat it as a minimization problem by writing down everything, another one is to realize light beams have already solved this problem for you, and the problem becomes much simpler when your river entry angle α and swimming angle β have to satisfy (sin α)/v_walking = (sin β)/v_swimming and the fastest path is the one which just happens to satisfy this angle constraint