The well-known ``do dogs know calculus'' problem optimizes the travel time from an onshore dog to an offshore stick, given different running and swimming speeds and a straight coastline. Here, we optimize the travel time between two points on the boundary of a rectangular swimming pool, assuming that running speed along the edge differs from the swimming speed.
"Minimizing Times Between Boundary Points on Rectangular Pools." Missouri J. Math. Sci. 28 (1) 2 - 14, May 2016. https://doi.org/10.35834/mjms/1474295351