Neither rounds nor longways persisted in American folk dancing proper, although both formations are found in children's games, and the still-popular "Virginia Reel" is a longways.
So take a piece of roving about 16 ins long and pull it apart longways so you have two 16ins long bits and tie a knot in the middle of one.
English country dances were usually either rounds dancers standing in a circle or longways dancers in two lines facing each other.