They said, what if mass puts a bend in this four-way here of ours? The more mass you have in one spot, the more bent that spot gets. So now pick out a spot A and a spot B, one on each side of some mass, and each at its own time. What does it look like when a body goes from A to B? You will say: A line. Well, yes and no. It is a line, but it’s also bent, as it goes past the bent spot. You see, this line will only look like a line if you can see all four ways! If you can’t see one of the ways, if for you the way you can’t see is what you call time, then you will see it as a line with a big old veer in it, half way in. Now, take a lot of mass, as much as our sun has, and pick spot A and spot B to be near the mass, and to be the same spot but for the time. Well, when you do that, the line from A to B in the four-way here will be an arc to you and me! An arc that will spin on and on, with that mass as the axis!