Here is another example. But we aren't able to make a scale model, or "picture" it in our minds.
You can easily picture a finite area that has no edge. Take a sphere, for example. A finite, limited two dimensional entity. The limited are of a sphere has no edge or boundary.
But, we can't readily imagine or picture a finite yet boundless volume. We tend to think of reality including an infinite space, with the universe expanding (or existing) at some location inside that space. And given a universe of finite volume and/or mass, we figure we could "get outside" the universe, into that empty space, and look back and see the universe.
But maybe, just maybe, it is not like that at all. Maybe "infinite empty space" does not exist. Even given a universe of finite volume and finite mass, perhaps the finite volume has no edge, no boundary, no "outside of the universe." Maybe space itself is finite! The notion boggles the mind, but it is exactly that notion that posters are attempting to express for your benefit.
Prove it, I can't. Heck, maybe I can't even express the notion well. But that's my best shot at it. Cheers. Ta Ta For Now.
Every argument you have, I have heard at least 1,000 times.
I keep asking a rather simple question:
Can you give me an physical example of these multi-dimensional mathematical theories. No "Flat Land" fictional books, but an actual physical example?
This should have been such a simple thing to do. For years, I was ashamed to even ask the question. It would make me look rather stupid and ignorant.