I like mechanical systems.
I like understanding when I wind open the throttle a cable connected to that twist-grip lifts a slide in a metal tube, allowing more air to rush through a chute across a pool of flammable liquid, and the velocity of that air draws vapour from the top of the combustible liquid and the resulting mixture of gasses flows into a sealed chamber where it’s compressed and ignited. The ignition and resultant explosion is confined in such a way that the only possible direction for it to expand is downward, pushing a plug of metal which is connected to an eccentric shaft so that the motion of the descending disc of metal is converted into rotational movement.
“It’s all a bit spooky, I think, and I don’t know if I can trust something I can’t see moving to do its work. ”