Imagine you are a bicycle, wheels, frame and all. Now you need to travel from A to B. The points A and B can be many things. A could be unfit, B could be fit. A could be overweight or obese, and B could be trim and athletic. A could be birth, B could be death (hopefully these two are a suitable distance apart). What will happen to your bicycle if there is a buckle in the wheel? How far will you get? What are all the possibilities?