Originally Posted by duga

Beings means exactly as it sounds...beings. We are 3d beings, so there would be 4d beings and 71d beings. We have no way of perceiving or imagining the totality of those beings, though we would be able to perceive 2 of their dimensions if those 2 dimensions happen to coincide with our particular 3 dimensional space.

Honestly, I can't explain it any better than those videos did. As far as actually interacting directly with a 4th dimensional being, I can try to elaborate on that a little. Starting with the 1 dimensional world...that means there are 2 directions to go. Since every other being in that world also has only 2 directions, the chances of interacting with them are pretty high. Even though they can't perceive the 2nd dimension, it still exists right along with it, only they now have 4 directions to go. Even though they could still very easily interact with the 1d world, the chances that a 2d being will interact with a 1d being is significantly diminished, if only because it has more "directions" to go while the 1d guys are stuck going left or right. The same applies further up the ladder...even though we could interact with a 4d being, since they have that extra dimension to wonder around in the chance that we will actually interact with them is very slim. We could even theoretically interact with 71d beings since they do exist right along with us, only the chance that they will directly interact with our particular 3d niche is INCREDIBLY low.