Of the Six Fundamental Machines inscribed by the Builder in the Cornerstone of Time, the Wheel and Axle lends itself to perhaps the most stupendous domain of potential recomplications. Picture the sky as a giant clockwork mechanismeach planet a semiprecious stone set in the rim of its own great wheel, ticking about the axis of a star that is in turn a chip of diamond studding the rim of its own greater wheel, one that inscribes a unique but interdependent path about the center of gravity of a galaxy that is itself less than a cog on a still greater wheel that in concert with hundreds of billions of others drives the engine of the Universe. Fractal geometry on a scale to beggar the imagination.
Now zoom in again to picture yourself on the rim of your own planetary wheel, observing the progress of a friend on the rim of another wheel in the same system. Assuming different rates of travel, to watch that friend is sometimes to see an apparent reversal in his course. This loop of retrogression, as it's known, stems from the fact that you the observer are yourself a passenger on a body in motion.
All things in the Builder's creation serve not only their own functions as objects but also as lessons for his children. Thus does the Wheel and Axle teach us that to move forward is sometimes to appear, perhaps even to ourselves, to slide back.