Kero wrote: > I have a generic solution which is perfectly happy with negative numbers > (and Bignums) which is unlikely to be the fastest solution at all. Now > you > allow others to use even more optimizations! Kero, You are perfectly right, I should have stated clearly in the Quiz description, that the domain is positive integers. There is no reason to include zero or negative numbers. The number of possible mazes is still infinity squared! Enjoy! Christer Nilsson -- Posted via http://www.ruby-forum.com/.