Other names--Duck to the Middle; Inside Arch, Outside Under. From eight chain thru formation: The center couples make an arch by raising inside hands, the outside couple (actives) duck through the arch into the center to take the next call. Those who made the arch do a California twirl (automatically). Finishes in double pass thru formation.
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.