A chess king is placed on a 8x8 chessboard. It has to make 64 moves, visiting each (of 64) squares only once, and to return there where it started. The path has to be with no intersections (a path looking like '8' is no good). For a loop, one can count the total number of horizontal + vertical (i.e. excluding diagonal) moves; let's call this number M. 1. Give an example of at least one such loop. 2. Give an example of a loop with the largest possible M. 3. Give an example of a loop with M=28. 4. Prove that 28 is the smallest possible M.