 Another was "blueprints," which allow players to get a general sense of a house's layout before entering and thus encourage setting up puzzle-based—rather than luck-based—vault defenses.Rohrer did not, however, want the game to be impossible, so he took the step of forcing players to evade their own traps before the houses would be accessible to others.The game has been placed in the public domain and is hosted on SourceForge.