Continuing Pit Week...
The previous pit-themed geomorphs were drawn in a cavern style; the pits might actually be natural, rather than man-made (or monster-made.) Here are two geomorphs using standard, square-cornered corridors, with obviously man-made square pits.
Geomorph F5 is a set of corridors with pits as obstacles. One pit is directly in front of a visible door; for extra devilishness, perhaps the door opens outwards. Another corridor section closely borders a room on a lower level; the pit in the corridor can optionally have an exit into this room.
Geomorph F6 is centered around a large room with several closely-placed pits. Crossing from one side of the room to the other is possible, but requires everyone to walk in single file and maintain their balance. There are only two obvious room exits, but one additional secret exit. Also, one of the pits is close to a wall; a little GM modification and that pit could have an exit into a new room not currently drawn on the map. The same could be done with another pit to connect it to an otherwise isolated corridor on the north edge of the geomorph.
The next planned geomorph(s)? Spiked pits.