A village is constructed in the form of a square, consisting of 9 blocks , each of side length ℓ, in a 3×3 formation . Each block is bounded by a bitumen road . If we commence at a corner of the village, what is the smallest distance we must travel along bitumen roads , if we are to pass along each section of bitumen road at least once and finish at the same corner?(Muscovite folklore) squaredistanceminimumcombinatorial geometrygeometry