When playing with this method, gamblers bet by adding the last two bets with each other. https://wantit.us/%EB%B3%B4%EC%A6%9D%EC%84%9C-%EB%8C%80%EC%B6%9C-%EC%8B%A0%EB%A2%B0%ED%95%A0-%EC%88%98-%EC%9E%88%EB%8A%94-%EA%B8%88%EC%9C%B5-%EC%84%A0%ED%83%9D%EC%A7%80%EB%A5%BC-%EC%B0%BE%EB%8A%94-%EB%B0%A9%EB%B2%95/