This dancing couple gave lessons to anyone watching at the Lowell Folk Festival. His hand placement, peripheral vision, and excellent anticipation kept them moving along the walk way almost undeterred by anyone attempting to walk by.
Note his right hand, positioned just so, on the small of her back. It would press to guide her forward or release to let her move back.
His peripheral vision was almost uncanny, catching the openings as they appeared or waiting for them to appear, keeping the movements going so that their dancing seemed all one carefully choreographed dance movement.
I am kicking myself for not finding out their names to provide the credit where it is due. The music was good. Their movements helped to make the music even better!