Factorio is interesting because the circuit system is pretty much designed for doing computation in. For a while I wondered whether it would be possible to build a computer in Factorio without using the facilities intended for it and instead Heath-Robinsoning it together out of other things. Trains, for example; an empty train is a set of "holes" that could be used to make a trainsistor?

Unfortunately there aren't a lot of reversible transformations in Factorio, or mechanisms for one thing to influence another without being consumed.