Drawn by Ludwig, the artistic inmate, the map reflects a prisoner’s mindset: eccentric yet skillful, as Gustave notes when praising its lining. It doesn’t describe the mechanics of the escape but signals the start of the plan, one that depends on digging tools smuggled inside through Mendl’s pastry boxes. In this way, the map both invites Gustave to join the scheme and serves as the indispensable element that makes the breakout possible — a clear causal prop in the narrative.