(He makes his own very thin brass coil springs to run the cables through.)
The magnetic hands were such a cool idea, and the way he builds the springs for the bowden cables in ep 2, gorgeous!
Automata are marvels of engineering. They're similar to computer programs, except their creators are expert artisans of both hardware and "software".
For anyone interested in this topic, I highly recommend the BBC documentary "Mechanical Marvels: Clockwork Dreams"[1].