Fort Impossibility is an enormous repository for mathematical curiosities. Among the priceless objects stored within its vaults are the Penrose Triangle, the Escher Cube, and the infamous Devil's Pitchfork. Naturally, nerdy thieves everywhere are anxious to steal these valuables to study their geometrical weirdness.

Designed by a team of brilliant mathematicians and insane architects, Fort Impossibility has a unique architectural feature intended to thwart invasion. Where ordinary strongholds can be conquered by capturing their highest point and using the height advantage to dominate the rest, Fort Impossibility has been constructed with such unusual geometry that no highest point exists within the structure. No matter where you are in the building, there is always a staircase leading upward! Therein lies the challenge to the would-be thief.

There are four towers, two entry staircases, twelve linear staircases, a center walkway, and a ground level. Each of these twenty features is worth 2 points. And, because of the unusual architecture of the building, each feature is more easily captured than defended.

Modified dice are used to give the upstairs player an advantage. A player attacking in a downstairs direction gets to use an 8-sided die, as does a player defending from upstairs. Attacks on level ground use the standard 6-sided dice. What does this mean? Simply that your armies will be nearly invincible if you stick to attacking downstairs, but will usually lose in a gruesome fashion if you insist on attacking upstairs. So choose your upstairs fights very carefully. You have been warned!

This game works best with 3 to 5 players.