Flint and steel is one of the oldest ways to make fire, striking a hard stone against steel to throw sparks onto tinder, so the sound carries an immediate sense of something being lit by hand. Online it has become a handy shorthand for ignition in gaming videos, survival clips and comedy edits, where a single strike can set up a campfire, a trap or an ill-advised plan. Its appeal has lasted because the metallic scrape and following crackle are easy to recognise even without any picture.