The sound is based on Apple’s Marimba ringtone, the default tone shipped with the original iPhone in 2007 and kept as a familiar option on later models. Its simple, upbeat pattern made it instantly recognisable worldwide, and it soon became shorthand in films, adverts and online videos for someone receiving a call. As smartphones spread, the tone moved from real handsets into memes and edits, where it is now used to stage fake calls, interrupt a scene, or trigger that familiar urge to check a pocket.