Everything here is play: push, pull and tap, and the engine answers. A diesel needs no spark plug. It squeezes air until the air turns hot enough to light the fuel all by itself. Air in, squeeze, boom, puff out - the four-stroke cycle, over and over.
Sizes and timing are simplified so you can see them. A real diesel squeezes its air into about a sixteenth of the room it started with, and each stroke takes a split second.