I'm starting another geomorph series this week: The G-series, Gears and Machinery. There will certainly be some traps and tricks, but not all of the geomorphs will have a single purpose: some of the machinery can be re-interpreted according to the GM's needs. Some may not have any function at all, other than to distract explorers.
The first G-series geomorph, though, has a more or less obvious fuction. There's a curved rock wall built on top of a large, horizontal gear. As the gear turns, it closes off either the northern or the southern passage; it seems impossible to go directly from the north entrance to the south entrance. Of course, any GM could map this without explicitly drawing the gears, but in this case the gears are exposed in the control room to the west; the eastern "wall" of this room is actually a vertical gear that drives the platform gear. Levers here control which way the gear rotates. Because the gears are exposed, characters can try crawling under the gears, jamming them, or breaking a cursed sword between them.