Yes, and the solution for a circle of radius r is easy(going straight, you don't need to walk more than 2r; if you turn anywhere, you risk walking more than tha

Yes, and the solution for a circle of radius r is easy(going straight, you don't need to walk more than 2r; if you turn anywhere, you risk walking more than that). Bellman put exact knowledge of the shape of the forest in the problem statement to make it nontrivial and therefore more difficult.