The Idea of Shell Worlds located in a massive machine

So here is the idea about it. The Machine keeps the Shell Worlds habitable and rotating. The Shell Worlds are like miniature worlds populated by living things and humans. However, each Shell World has its own uniqueness such as a Shell World of mostly water, Shell World populated by Mons and other Shell Worlds.

You could actually take all the material on the earth and create a giant inside out world with a much greater surface area. Yours would essentially be a folded up version. To make it work, you will need fantastic gravity that does not function like normal gravity. You will also need impossibly strong construction materials.

I heard of this kind of world before, but forget where.