For me, I try not to get too hung up on geometric and mathematical descriptions of the 4th dimension. Lets face it, even those explanations are just imperfect, 2-dimensional representations in a 3-dimensional reality. Sometimes I think the left brain just obscures our view of things. I think one has to think of time differently, to conceive of 4-dimensions. My explanation is this...stop thinking of time as linear and imagine all time as existing simultaneously. Imagine the physical universe from beginning to end, and everything in between, existing together as one. Think of it as a big, beautiful piece of art. Each, galaxy, solar system, star, planet, moon, life-form etc....each would manifest itself as it's own unique "brush-stroke" in this mind-boggling, 4-D sculpture. Since we don't really understand exactly what happened at the beginning of the universe, and we don't know what's going to happen at the end, you have to fudge a little there. Who knows, it may be cyclical. Anyway, that's the concept in my opinion. From this linear view of time in our dimension you cannot see this, but you CAN imagine it.