I am not sure why the borders of all these walls are bright. Shouldn’t the room be dark? The edges are close but not overlapping. When they overlap they start flickering and I get warnings/errors when building. So I don’t think overlapping is a good idea but I can’t figure out how to make a dark room. In the examples, the rooms are built the same way but those are dark where as mine doesn’t turn out to be dark.
Here are the pictures of the room from the inside and outside: