Using a marble and a board bent in one place, (later they used metal piping run in different ways) they tried to explain. The marble would roll slower at first ,then as it reached the bend in the board it would speed up on the more downward angle. The more downhill the angle, the faster it moved.
Hence, the terms "Around the Bend", "downward spiral", and "Over the Hill" came to be.

But as the saying goes, "It is all mind over matter. If you don't mind, it doesn't matter."
