I have a few questions to help me out with understanding this more fully than I do.
1 - What analogy is easier to follow-Alkaline's one he uses, the length, height but not breadth one for the 2D world, or the one used in Flatland, of all geometric shapes, in a world of length and breadth, but not height?
2 - Would the fourth dimension be one like our length/breadth that we can walk on, or like height, "above" us, or something else, or do we not know, or is it irrelevant!
Welcome to the Forums, for me!