Pipe organs generate their sound thanks to fluid dynamics, but the “fluid” that makes the music is up to whomever builds the instrument. A traditional organ usually blows air through their pipes, while a calliope relies on heated steam. Does this mean someone could hypothetically construct a version using propane? Bartle has intermittently provided updates on his “fire organ” for months, showcasing a trial-and-error approach to designing and building the oddball instrument. A previous version of Bartle’s fire organ relied on pilot lights to spark the propane, but those frequently broke and also wasted too much fuel.