--- Thane Plambeck <thane@best.com> wrote:
Monckton's Eternity Puzzle went bad on him, but is it possible to create similar puzzles with a reasonable expectation that no one is going to solve them over, say, a three year time frame, even with computers and extreme cleverness? It does seem to be a good idea to sell puzzles with big prizes for solutions if only one could know that they're attractive enough to sell and unlikely to be solved before the time limit...
When coloring is added to the pieces, the puzzle can become much harder. For example, in http://www.mathpuzzle.com/threecolor.gif , no two pieces of the same color touch each other. Make a another rectangle of the same size, with the same property. The hexominoes and tetrominoes can make 6 6x6 squares. http://www.mathpuzzle.com/Hamlyncube.GIF These have been three colored. Arrange the pieces to make a 12x18 rectangle so that no two pieces of the same color touch each other. Hamlyn solved this. Rearranging http://www.gamepuzzles.com/polycub2.htm#HP so that no two pieces of the same color touch each other is currently non-solvable. --Ed Pegg Jr.