On February 14, 1924, early in the five-year courtship of Ken Slifer and Caryl Dutton, Ken created a Valentine that read, "Flivverin' with you would be jes' like ridin' in a Rolls-Royce with anyone else." His precise drawing of a classy 1924 Rolls-Royce is the card's centerpiece. A "flivver" was any ordinary car similar to his family's assembly-line Model T Ford, "Lizzie." Ken and Caryl, then both 18, were students at Bucknell University, in Lewisburg, Pennsylvania. From the beginning of their courtship, Ken and Caryl frequently exchanged notes and letters. Eventually, they were writing...