The windows are the ones with a red border. You've got to place them on both floors. I'll add that.
Yes, I thought I recognized them.
There's a few things mentioned in here that I never realized were possible. Nice discovery!
Edit: I found another use for your neat little trick!
I, for some inexplicable reason, have a hard time building houses without using foundations. I think it has something to do with the fact that I like houses that have front/rear porches. They just look better to me. But early on, I discovered an issue: placing the staircase to the basement by an exterior wall. Since there is no foundation on the outside of the house, this left a gap between the wall and the ground. Your trick fixes that problem perfectly!
First step is to place the stairs where you want them:
Next, you add the foundation around the stairs, but you add a few extra sections around the outer edge to support the wall:
Then, you build your walls, after which you remove the outer sections of foundation, plus the notches:
After that, you install the foundation-sized wall the same way you described above:
And finally, you fill in the notches:
After that, you can apply whatever wall covering you are going to use on the rest of the foundation, and from the outside that short section of wall looks no different from the rest of the foundation.
I want to thank you for helping me to solve a problem I've had for years!