The puzzle for this issue concerns a person taking a walk through a five block by five block grid of city streets (i.e. 25 solid blocks arranged in a 5x5 square with streets running between. The person starts in the northeast corner and wishes to take a walk through the grid never covering the same street twice and returning to the northeast corner (passing through the same intersection more than once is permissible). The puzzle is to find the longest walk that can be taken that fulfills these requirements. After solving that puzzle you may wish to try to answer the same question for a 7x6, 6x6, and in general mxn grid of streets.