This isn't related directly to Perl, but I was researching Minesweeper with the idea of creating a program like that, and I discovered that someone proved it to be an NP-complete problem (external link). If you manage to make an efficient algorithm for it, you'll also be able to break a whole lot of current encryption algorithms.

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I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated