"Knight's Tour" is to lay out a route across the chess board in such a way that the Knight lands on each square only once. It remained a mystery for 230 years from the times of Euler. The problem was solved in 1990s by a group of German students. More about that at: http://www.behnel.de/knight.html
The solution given here as a widget on the left margin is one of a smaller sub-set of the millions of possible routes. This route is cyclic, i.e. the Knight returns to the square from which it started the conquest. Thanks to Vaithy, for introducing this riddle to me at law college.