3. The Third Dimension – A Fold
Imagining the third dimension is the easiest for us because every moment of our lives that is what we’re in. A three dimensional object has length, width, and height. But here’s another way to describe the third dimension: if we imagine an ant walking across a newspaper which is lying on a table, we can pretend that the ant is a Flatlander, walking along on a flat two-dimensional newspaper world. If that paper is now folded in the middle, we create a way for our Flatlander Ant to “magically” disappear from one position in his two-dimensional world and be instantly transported to another. We can imagine that we did this by taking a two-dimensional object and folding it through the dimension above, which is our third dimension. Once again, it’ll be more convenient for us as we imagine the higher dimensions if we can think of the third dimension in this way: the third dimension is what you “fold through” to jump from one point to another in the dimension below.