The Multiverse. Welcome to confusion.
The Multiverse is a theory circulating in the Nationstates community regarding the topic of- Well, everything. The Multiverse is what's used to explain geographic claims, movement through space and time, and anything else one might have trouble disecting.
Earth and Cake
Regarding Geographic claims such as RL Earth. The Multiverse is the theory used to explain conflicting claims. If Nation A claims France, and Nation B claims France, conflict will obviously occur. Seldom is it seen that conflict does not lead to War. To avoid War, the Multiverse theory can be used. France A will lay in Plane 1, and France B will lay in Plane 2. Dimensions!
Now you may say, "But what are these Planes you speak of? Alternate Dimensions? What's that?" Well, I'm glad you asked! Let me describe it like this- A cake. Imagine the Multiverse as one gigantic cake. For all intent and purpose, the Multiverse is a seven layer cake.
France A lays in Layer 1, France B lays in Layer 2. They are parallel exactly to each other, just existing in different Dimensions, in the case of the Cake, the Dimension of height. As I see it, Nationstates is a Cake! Each layer of the Cake is a different Dimension in which a Nation can exist. With the extremely large number of players on Nationstates period, one Dimension is not enough when most Nations prefer to stay on Earth, in Modern Tech.
A Word on Earth Infinity
You may ask though, "I see an Earth I, and an Earth II! What does this mean? Two cakes?" Let me put it this way. Earth I, Earth II, Earth III, Earth V, RL Earth, Terra, NS Earth, Earth 2010, A Modern World- All these labels can be simplified. Each label regarding a New Earth and whatnot, can be seen as a label for any [ Layer/Dimension ] of the cake.
"But sir, what if France A and France B want to interact?" Well Timmy, I'll tell you what happens! One such way something like this can be arranged, is in something I call Polka-Dots. France A and France B can converge in between Layers. Right in the icing that seperates the Layer 1 and 2. In this way, the Nations share the land, each overlapping the other wholly. If one wants to interact with another, it should be played as following. Say you are Rep. of France A, travelling from Point A to point B, which lays in France B. It should be that one travels from Point A France A, to point B, France A. While one would use the geographic terms in France A, point B will be a sort of dot floating in France A which encapsulates Point B, France B. Hence, Polka-Dots. Think of it as the Pudding seperating the Layers of the cake, seeping into a crevice in Layer 1.
Confused yet? It gets more befuddling, worry not.
Another theory, one that pertains more to traveling the Multiverse, but is related to Polka-dots.
What if though, it's a larger area? Say if France A goes to War with France B. Troop movements? One might say regarding that, "Wtf." The Yo-yo effect comes in handy when describing large scale, important movements between two dimensions. Now, one could say, "Why not travel up through the pudding?" Well, you can't very well dig down through your Layer, and fall from the sky of the next, can you? And you can't very well fly up through the Pudding, and come up through the bottom of the next Layer?
Well here's why we call this a Yo-yo. Say you are to invade France B. France A deploys a massive ammount of troops, and launches it off from it's coast. Allow the troops to travel a set distance away from France A, decided on from both sides, then turn around, and follow the path the took back. When they arrive, they will arrive at France B. Like a Yo-yo, you snap it away, but snap it right back to the same position. Except when it snaps back, it's a different hand holding the string.
Now we can discuss something called a Stargate. This is one thing that is used by Future Tech Nations to explain interdimensional travel. It also though, can be used by Nations leaning more towards Fantasy Tech. Simply- There's a hole, you jump through it, and you arrive somewhere else. All wanking aside, that is what this method is. This method is also dubbed as a Wormhole, Stargate, Portal, Tear, and Space-Time Continuum Thingy.
Also described as a Manhole theory.
Attempt at even more Simplification-
On one level, "Street," man jumps in Manhole, travels down through the "Dimension" of height, and exits in a new level, "Sewer."
The Yo-yo effect is just another way of explaining interdimensional movements. This of course, like Polka-Dots, can be used on many levels of size, ranging from an Assasination in the next Room, Terrorist Raid on a Village, or full scale Invasion of another Nation. All possible methods of interdimensional travel.