Light is fast, but not arbitrarily fast. A pulse crosses exactly one cell per tick. The longer way arrives later.
That is the whole rule. Everything else in this game follows from it.

A source sends light. A receiver waits for it — in the right colour, on the right beat. Between them lies an empty site.

You draw conduits like a line on paper, press Run and watch. If the light arrives, the order is filled. If it comes early, late or in the wrong colour, the game shows you exactly where — and you draw the line differently.

Nothing breaks, nothing runs out. Build as long as you like.

Three numbers stand above every machine: ticks, cost, footprint. They contradict each other. The fast answer is rarely the small one, and the cheap one almost never the fastest.

Stop at the tick mark if you want. Or build the same machine three more times — and measure yourself against everyone who did the same.

New parts arrive one at a time and explain themselves on the site, not in a manual. Each brings an idea, and every idea makes yesterday's site look different.

What lies on the board in the later chapters is not written here. Find that out yourself.

The editor is the one the game's own orders were built with: your own orders, your own parts, whole chapters. One code, and somebody else plays what you made. The Steam Workshop holds what others built.