From double pass thru formation or parallel waves: Centers or everybody do as per call (Turn Thru, Scoot Back, etc.). Trailers or those facing in then weave by those coming out of the center to meet the other trailer for a left handed single hinge in the center. Those facing out Quarter Right to form parallel waves.
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.