An angry, recalcitrant ram enters the paddock from the southwest gate and charges directly at you at a constant speed. I'm especially on the hunt for Riddler Jr. problems -- puzzles that can stoke the curiosity and critical thinking of Riddler Nation's younger compatriots. The problem's submitter, Po-Shen Loh, noted that the bounds on the length of the optimal journey can be found by using the graph theory concept of a minimum spanning tree, which connects all vertices in a graph (Pokéstops in this case) in the most efficient way. The length of the optimal journey is bounded between the weight of the minimum spanning tree of the graph created by the Pokéstops, and two times its weight -- it's possible you'd need to double-back, after all, retracing your steps.