From a wave or two-faced line: Centers Trade while the ends Crossfold. From a wave, ends in Z-formation with couples facing; from a two-faced line, ends in Z-formation with couples in single file. NOTE: It was Curl the Line that introduced us to the Z-formation.
Sie Watson 1964
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.