If you place Corridor Edge B block on its side like this: When you jump onto the "floor" part of this, you fall through to whatever is underneath! If the wall is vertical (i.e. the proper way up), you can't walk through it, it's only when the side is on the ground Whilst it makes a cunning POI trap, it's a bit annoying. This is in a creative game, I haven't tried in survival yet.
It's also a nightmare to paint/texture the inner side. You have to point to the edge of protruding bar to hit it.
