Here are two more takes on the crushing walls theme for the Gears and Machinery G-series of geomorphs. I'm offering a two-fer because I have more G-series geomorphs in the works and decided to finish up the crushing walls all at once.
Geomorph G11 is another hidden pit trap that drops the unwitting into a room with crushing walls; the difference here is that the walls pivot inwards until they meet. This makes it difficult to slip around one of the walls into the gear room, but not impossible. Also, I left part of the gears exposed in the trapped room, although the GM is free to interpret the gears as being just under the floor.
G12, on the other hand, is a single moving wall that pushes towards the opposing stationary wall. Instead of a trap door, the trick here is a false door plainly visible from the entryway. Trying to open the false door triggers the trap. If the adventurers have spiked open the exit, they have a chance to escape. There's no chance of getting behind the moving wall from inside the room without magic, although again, if the entrance is spiked open, someone outside the room could slip behind the wall as it moves past... which gives access to the secret door in the gear chamber, and possibly access to an otherwise difficult to reach section of the dungeon. It's not just a trap, it's a puzzle!
I'll be putting up a temporary PDF of the first dozen G-series geomorphs in a few days, but there are actually more to come.