This blueprint implements a NAND gate, which could theoretically be used to build a computer in vanilla Satisfactory.

The way it works is by using the only component that can use electricity to impact an the direction of a flow: the humble pump. In combination with an overflow gate and a fuel generator, it allows to make a building that takes as input some fuel, an electric connection A, an electric connection B, and that powers an output connection C if and only if not both A and B are powered.

See https://www.reddit.com/r/SatisfactoryGame/comments/wm9kni/satisfactory_is_functionally_complete_working for more information.

This is mostly a proof of concept: it suffers from the fact that pipe overflow is very slow, and hard to make reliable; in practice, it might take minutes for a change in input to be reflected in the output.

One example of a concrete application of that kind of logic gates would be to use a different light controller when a factory does not have power, or to power an emergency fuel generator and some red alert lights when the main grid loses power.