SOS in Morse code, three dots, three dashes and three dots, was chosen as the international distress signal in the early twentieth century because the pattern is simple, unmistakable and easy to send even with basic equipment. It was originally used by ships and radio operators to call for urgent help, and it later entered everyday language as shorthand for any emergency. Online, the beeping pattern is now widely reused in videos, memes and edits to signal trouble, panic or a comic cry for help.