Henry Ernest Dudeney/Modern Puzzles/220 - The Fly's Tour/Solution

by : $220$

 * The Fly's Tour

Solution
's answer is:


 * Before you join the ends give one end of the ribbon a half-turn, so that there is a twist in the ring.
 * Then the fly can walk over all the squares without going over the edge,
 * for we have the curious paradox of a piece of paper with only one side and one edge!

has of course described a Möbius strip.

The author of this page is not convinced by his exposition, because at least part of the paper will end up flat on the table, and the fly may have trouble negotiating that bit.