We exist in 3 dimensions, but only move in 2. We exist backward and forward, left and right, and up and down. Just have another person stand still and check them out. But, in normal travel, we only go left or right, and forwards or backwards. (If anything, 2.5 dimensions, unless you back your car up in very odd amounts.) Our cars do not fly yet, so we don't regularly go up and down. I don't know, I just found that very fascinating. It hit me on the bus, watching another car travel while traveling. I find a lot of things fascinating. :;,