Pits and downward stairs without a border.

The attached image should make more visible what I mean.
The red markers:
Two screenshots of the same stairs, but from a different angle.
The stairway leading from the upper level, down to the "pit" is odd. The walls to the north and the south of the stairs simply shouldn't be there.

The green marker:
Here's a problem with both the border of the pit and the walls of the staircase.

On top of that: the bottom of the "pit" should show the room below, but that feature hopefully will be there once the multi-level buildings will be a fact.