

Three doors, each leads to 20 doors. The correct door leads to 20 more doors in the correct area, the rest will lead to 20 more doors each, all traps. Some rooms are insulting, with no trap and a single copper on the floor. One of those rooms will lead to 20 more doors, one of which is the correct door.
The most important part of it is “is there anything you’d like to admit, before we take the test?”