Monday, September 25, 2006

Guarini's Problem


The earliest chessboard puzzle dates from 1512, almost 500 years ago. Guarini's Problem involves four knights, two white and two black, at the four corners of a small 3X3 chessboard. The white knights and the black knights need to exchange places. A knight can move on a chessboard by going two squares in any horizontal or vertical direction, and then turning either left or right one more square. It is a relatively simple puzzle to solve, even by trial and error.
The knights must march around a cycle, all in the same direction, either clockwise or counterclockwise, until their positions are exactly reversed.

No comments: