Why don't Quarter horses and Paints race together?

Yes, Quarter horses and Paints are essentially the same.

History will have it; the American Paint Horse shares a common ancestry with the American Quarter Horse and the Thoroughbred. A registered Paint horse should conform to the same "stock horse" body type desired in Quarter Horses: a muscular animal that is heavy but not too tall, with a low center of gravity for maneuverability, and powerful hindquarters suitable for rapid acceleration and sprinting. When the American Quarter Horse Association emerged in 1940 to preserve horses of the "stock" type, it excluded those with pinto coat patterns and "crop out" horses, those born with white body spots or white above the knees and hocks. Undeterred, fans of colorful stock horses formed a variety of organizations to preserve and promote Paint horses. In 1965 some of these groups merged to form the American Paint Horse Association.

:)

LOL! I have to admit Chauffeur Extraordinaire answer is FUNNY :)

If you get paint all over your quarters they won't work at the arcade...