It actually is - the concept is the same (warping of lower dimensions in higher dimension). The only difference is that with a torus/sphere, the ends of the paper meet. Sure, in the torus example you could theoretically see your own back (btw, this is impossible in your snake example), but I don't see what this has to do with my point.
No.There is a fundimental differance on the topology of the shape if the "Ends connect" or if its just a crumpled shape. For example the Gas/water/Electricity to three houses problem without crossing the connections, cannot be solved on a piece of paper (2d surface), no matter how crumpled (NOT folded),it is. But is can be solved on a torus, because they are mathematicaly different shapes. And no, its not impossible in the snake example. (Because its analgus, not the same as; The universe is the 2d plane/Tourus)
No matter how your universe is warped/twisted/torused/crumpled, you're stuck in that universe, unless you hit an "edge
Unless its "Shaped" so as not to have an edge, and loops round the same way as your torus. (Klien Bottle) In which case it is a diffent shape to a Universe that doesnt loop round What I'm saying is there's no use for Full 4-dimensional space in a 3D game, unless the viewer is restricted to 3D or 2D views. A 4D renderer (as in the original topic) would be useless, because humans don't have 4D eyes.
And what I am saying is if you travel in one direction and it loops back to your start possition, then it is already 4D. And as Ive said the original topic was not implicetly about a 4D render, just Dimentions.