Several centuries ago, an alchemist sat making a number of final adjustments.
The miniature globes on their thin stems, representing the Solar System, remained motionless as he carefully performs a final tweak here, another there. There was a complexity of connected cogs designed to drive the orrery; a small model that showed the relative positions of the planets and moons. This was something he had been working on for the better part of his entire lifetime. He carefully releases the minute counterweight and smiles with deep satisfaction as the entire configuration noiselessly begins to turn… backwards! After watching the array of interconnected movements for a while, and with the greatest of care, he attaches the back plate. Sitting back, he looks at what he knows is his ultimate work.
At long last, it was time to take it to the only people that would have any understanding of what he had created, his fellow members of the alchemists’ society. He slowly lifted, what was now a completely sealed item, and set it down onto a thick blanket. Wrapping all of the material around it, he slowly made his way out into the street. He was mindful of the delicate nature of what he was carrying.
Holding the bundle tight against his chest he began the short walk that would take him to the meeting place. He was certainly wise enough to realise that the sheer thrill he was experiencing had to be tempered. What he was about to do needed great care, lest all of his many years of hard work should undoubtedly come undone.
He knew only too well that the slightest disturbance of the device, now that it had been set in motion, could easily bring about an irreversible alteration to the current state and future performance of the Solar System!
As he approached the building, his foot caught on something and he fell over…