There's a large and very loud AODD ("air-operated double diaphragm") pump at my workplace that operates intermittently, and has weirdly taken to exhibiting more and more complex behavior when it vents air pressure. Instead of just venting air at regular intervals, it'll do stuff like intersperse widely spaced bursts with fusillades of closely spaced bursts.

It's gotten me to fantasizing idly about a horror story in which someone working a night shift in a noisy factory starts becoming convinces that someone or something is attempting to send messages to them via the timing and spacing of the various bangs, clanks, and other factory noises.