" But after World War II, the brothers realized they were running hard just to stay in one place. They weren’t building volume even though their parking lot was always full. So they did a courageous thing. They closed that successful restaurant in 1948 and reopened it a short time later with a radically different kind of operation. It was a restaurant stripped down to the minimum in service and menu, the prototype for legions of fast-food units that later would spread across the land. Hamburgers, fries, and beverages were prepared on an assembly line basis, and, to the amazement of everyone, Mac and Dick included, the thing worked! "

― Ray Kroc , Grinding It Out: The Making of McDonald's