Ok, for anyone who doesn't quite get what's going on, think of it this way. This is a 2D image of a 3D "snapshot" of a 4D world. In other words, yes, you are only seeing 3D at any given point in time. Why not just make a snapshot of a 4D world? Because a) we cannot visualize it, and therefore cannot really make it, and b) our eyes physically can't see more than three dimensions anyway (technically, we actually can't even see in 3 dimensions, just 2; we use various subconscious techniques to visually understand 3D, but we still can't see it).
An brown townogy (kind of). If distance is 1D, and distance per time (velocity) is 2D, then distance per time squared (acceleration) is 3D. To reach a level 4D you could do distance squared per time squared (acceleration on a plane instead of a line). Not a perfect brown townogy, but those are hard to come up with when dealing with greater than three dimensions.