It's always interesting to see new game mechanics crop up simultaneously in different titles.
With long development cycles it's usually not a result of out and out plagiarism (though that happens with the inevitable knockoffs).
There are two games on the way that utilize a way to 'fold' the video game space from 2-d to 3-d: Super Paper Mario and Crush.
Now I'm not saying that these games are the first to use this technique. A lot of innovative systems come from obscure, independent sources that filter to the major developers by word-of-mouth. So I wouldn't be surprised to learn about an indie title with the same concept.
I'm fascinated because now instead of having to struggle with explaining the concept of multiple dimensions it is now possible to demonstrate precisely what we mean. Our children are going to be grasping constructs that were, thirty years ago, restricted to departments of higher mathematics.
If you combine the mechanic used in Crush with the time-manipulation of the Prince of Persia series, then you have a game that gives the player the ability to interact with three of four dimensions (2-d, 3-d, 4-d).
How would you create a fifth-dimensional gameplay element? Would it consist of playing the same level in different ways and having to manipulate all of those multiple dimensions in order to unlock forward progress? What about nth-dimensional gameplay? A game of Spore that allows you to create parallel timelines? The Sims with time travel, where every attempt at creating a paradox splits the timeline and spawns an altered universe?