This is a simple room, but one which kept my own players puzzled for some time.
At the end of the hallway, the players pass through a simple opening into a circular room. The room has a stone floor, and walls of bronze which gently curve inward at the ceiling, rising to a point in the center. The walls may be engraved or otherwise adorned, but the room itself is empty. If the players decide that this is merely a dead end, it is important that they be able to go back through the dungeon and take an alternative route.
If the players choose to tap the walls, they will find most of them to be solid. However, there are definite hollow areas which echo when tapped. Closely examining the floor where the ceiling meets the wall will reveal that the bronze walls are fitted into a groove in the floor which extends all the way around the room. This groove is most obvious where the players entered the room. However, given the generally poor condition of the floor, characters will not notice this groove unless they pay special attention to that doorway.
In fact, the bronze cone has special ball bearings beneath it, and can be turned freely. It is heavy, But a concerted effort from a strong character, or two characters with strength 10+, is sufficient to slowly turn the room at a speed of 1/4 rotation per game turn (10 minutes). More characters working together will be able to turn the walls proportionally faster. As the wall turns, the opening moves, revealing previously hidden passages behind the bronze wall.
The danger, of course, is that by turning the cone the players are cutting off their means of escape back through the dungeon. Unless they have enough people to turn the bronze cone very quickly, they will be forced to face any dangers they reveal.
I like this a lot.
A question: when constructing these dungeon puzzles, do you give thought to their original purpose? For example, do you have ideas for what the original purpose of this architectural feature might have been?
Primarily, I focus on creating a room with a challenge I find both interesting and unusual. Often times those elements connect strongly to a theme. For example, last week’s Hanging Crown Dining Hall is obviously a monument to a dead king. But I didn’t set out to make a monument to a dead king, I set out to make a puzzle.
For rooms like this, I suppose I could come up with justification if I thought I needed to. It’s the kind of thing I can see someone building if they wanted to slow down people moving from point A to B. Perhaps it is between the entrance and the throne room, granting not only a defensive benefit, but allowing the occupant of the throne room ample warning of anyone approaching.
Now that you mention it, when designing dungeons I tend to make a room either a “theme room” which gives the players some insight into the original purpose of the dungeon and perhaps contain a simple trap or monster, and “challenge rooms” like this one which often don’t have much to do with the dungeon’s “story.”