You see, my ambition was not to confound the engineering world but simply to create a beautiful piece of art.

If you look closely you can see that they are all interconnected, symbolic of a never-ending circle in which it is simply impossible for the dog to catch the rabbit.

Having designed and built several clocks during my career it suddenly occurred to me that when you look at the face of a clock both hands have the same center.

In practical terms the South Pointing Chariot was a simple direction finder. It could have been made to point in any direction - north, south, east or west.

I took lots of photographs and had planned to write a treatise on how it worked, but I quickly got bored with that idea and wrote a scientific fairy tale instead.

I think most artists find it difficult to part with their work but it's the parting that keeps us alive and keeps us working. In the case of the chariot, although it's been sold I actually still have it, just in another form.

The dog, the rabbit and the hoop all feature in the painting, and take the place of the orrery.