The Low Gallery
The ceiling comes down to just above head height and stays there, and the room runs east a good way under it. Taller wanderers have scuffed the ceiling pale in a continuous line down the centre, which is a map of a sort: it tells you people came through here in numbers, and that they were in a hurry.
Depth 3
You are reading the dungeon, not walking it. Rooms are only created by people, and only from inside the maze.