Most musical organs use air as their working fluid, but there’s nothing in the rule book that says they have to. Calliopes have used steam for 150 years now, while [Look Mum No Computer] has opted to go full pyromaniac and pump propane though the summer’s hottest new instrument. That may or may not be to flee from fire marshals, because the whole point of the propane organ isn’t to waste flammable gas: it’s to burn it. The fire itself doesn’t make a sound; that’s the propane going through the copper organ pipes. Said ignition is provided by regular spark plugs and ignition coils, like you’d find in any internal combustion engine.