I'll draw it kind of parabola looking. Although I could have done it general, but just to make things a little bit simpler for me. So I'll draw it kind of parabola looking. So that is, if we call this a y-axis, we could even call this y equals s of t as a reasonable way to graph our position as a function of time function. And now let's think about what happens if we want to think about the change in position between two times. Let's say between time a. Let's say that's time a right over there.