The line comes from The A-Team, the American action television series that ran from 1983 to 1987. Colonel John Hannibal Smith, played by George Peppard, led a team of former soldiers who took on missions while on the run, and he closed many episodes by celebrating a scheme that had worked despite the odds. The phrase became his trademark sign-off and a shorthand for clever planning in popular culture. It spread through reruns, clips and memes, and creators still use it today because it instantly signals a plan falling neatly into place.