The William Marvy Company's barber poles, encased swirls of red and blue above a rounded stainless-steel base, hang on street corners around the country. The company began creating the vibrant signposts in St. Paul three generations ago. Modern versions of the bloody rags used by surgeon-barbers in the Middle Ages, barber poles are well-known icons, but the Marvy family story is largely unknown. From his humble beginnings as the son of a Latvian émigré...