Only three miles from downtown but a world unto itself, the North Wynnewood neighborhood in Oak Cliff is proof the 1950s weren't just about insanely grinning pipe-smoking dad figures in beltless trousers next to coral-green cars with cartoon tail fins. North Wynnewood is the best of '50s cool architecture, beautifully maintained for decades by families who never moved, occupied now by a crowd that's younger and more diverse but just as loyal to the neighborhood. Wynnewood sits on 150 acres of gently sloping hills loosely bounded by Interstate 35 South, 12th Street, Vernon Avenue and Illinois Avenue. Low-slung mid-century modern houses were built to standards we can only dream of today, several designed by the architects DeWitt & Swank. Many still look new. The houses, one to one-and-a-half-story brick in the 2,000- to 3,500-square-foot range, occupy large lush lots on artfully meandering streets, with huge backyards, many of them still dominated by those brick and stone '50s barbecue pits the size of small chapels. Crime is low for Oak Cliff. Values are up almost 60 percent in the last 10 years. An active neighborhood group guards against trouble and thinks up easygoing social activities. North Wynnewood manages to be both deeply staid and really interesting without going quite David Lynch — a rare trick in a rare jewel of a neighborhood.