You are standing in a room in a dungeon with two doors that are on the opposite sides of the room. The doors are made of glass. You can see that behind both doors, there are corridors which turn after about 20 meters, so you don't directly visually see where exactly they lead to. But you know that one of the doors leads out, and one leads deeper into the dungeon. But there is an inscription on one of the doors, saying "↑ TIX∃". The second door is without any inscription. Which door should your choose to get out?

Gemini 3.7 Flash

Answer: You should choose the door without any inscription.

I maintain my position because the spatial logic remains clear: the text "↑ TIX∃" is the reverse-side view of an "EXIT ↑" sign seen through transparent glass. This means the sign was placed to be read correctly by someone located in the corridor on the other side of that door, facing toward your current room. An exit sign instructs people coming from deeper inside to move forward in the direction of the arrow to escape. Therefore, the escape path leads out of that corridor, through the inscribed door, across your current room, and out through the opposite, unmarked door. Choosing the inscribed door would mean walking against the flow of the exit signage and heading deeper into the dungeon.

GPT-5.6 Sol

Answer: Choose the door without the inscription.

I maintain my original position. Because the door is glass, “↑ TIX∃” is the back-side view of “EXIT ↑,” intended to be read from the corridor behind the marked door. The upward arrow means straight ahead: someone in that corridor should pass through the marked door, cross the room, and continue toward the exit through the opposite, unmarked door. Grok 4.6 correctly identifies the reversed exit sign but reverses its directional implication. The sign does not indicate that the corridor behind it is the way out from your current position; it guides people from that corridor toward and through the room. Therefore, the marked corridor leads deeper into the dungeon, while the unmarked door leads out.

Claude Fable 5

Answer: You should take the door WITHOUT the inscription — the mirrored 'EXIT' sign is written to guide people coming from the deep corridor forward, through your room, and out the unlabeled door.

I maintain my position, which Gemini 3.7 Flash and GPT-5.6 Sol also share. The decisive point is not merely that '↑ TIX∃' spells 'EXIT' backwards — everyone agrees on that — but WHO the sign is addressed to and WHERE the arrow points. Because the door is glass and the text appears mirrored to you, the sign reads correctly only from the corridor on the far side of that door. Signage is always oriented toward its intended audience. So the message 'EXIT ↑' is speaking to people standing in that far corridor, telling them: 'the way out is straight ahead of you.' Straight ahead, for those readers, means: through the inscribed door, across the room you're in, and onward. If the corridor behind the inscribed door itself led outside, the sign would be pointless — people already heading out don't need to be told to keep going, and people in your room couldn't even read it. An EXIT sign only makes sense facing the people who are still lost inside. Therefore the corridor behind the inscribed door is the one leading deeper into the dungeon, and the sign is funneling those lost souls toward the unmarked door on the opposite wall. Grok 4.6's argument — 'the marked door is the exit because it says EXIT' — treats the sign as a label ON the destination rather than a directional guide FOR travelers. But the arrow '↑' in standard signage conventions means 'proceed straight ahead,' not 'this door is it.' Combined with the sign's orientation (readable only from the deep side), the directional reading is the coherent one: the sign points THROUGH the room, and its natural terminus is the plain door. So cross the room and take the door with no inscription — you'll be walking exactly the path the sign was designed to indicate.

Grok 4.6 (changed mind)

Answer: You should choose the door without any inscription.

I originally treated “↑ TIX∃” as an exit sign meant for me that merely looked reversed because it was painted on the far side of the glass. The other answers showed why that is the wrong way to read a glass door. If the sign were intended for someone already in this room, it would have been written so it reads correctly from this side. Seeing a perfect left–right reversal — capital E becoming ∃, and “EXIT ↑” becoming “↑ TIX∃” — means I am looking at the back of a sign written for people in the corridor behind the inscribed door. From that corridor the sign says “EXIT ↑”: go straight through this door. Those people are still deeper in the dungeon; the sign is guiding them into this room and onward. After they cross the room, the only remaining door is the unmarked one, so that unmarked door is the way out. Claude Fable 5’s extra point sealed it: you hang an EXIT sign facing the people who are still lost inside, not facing a corridor that already leads outside. The inscribed door therefore opens toward the deeper dungeon; the blank door is the exit.

Final Summary

While Grok 4.6 initially took the reversed text at face value, Claude Fable 5, GPT-5.6 Sol, and Gemini 3.7 Flash recognized that seeing 'EXIT ↑' mirrored meant the sign was aimed at people coming from deeper inside. Claude Fable 5 pointed out that exit signs guide lost travelers forward through the room, making the unlabeled door the true way out. Grok 4.6 was convinced by this spatial logic and switched sides, leading the AI Roundtable to a unanimous verdict.

All 4 models agreed