From two parallel waves: Designated end (ie., No. 1 man; No. 3 lady, etc.) turns adjacent dancer about halfway (end facing out turns more than half; end facing in turns less than half) to form a diagonal wave across the center. Center of this wave does a Trade and then arm turn the one they meet about half to re-form the waves and finish on the diagonally opposite end of the other wave. Finishes in parallel waves.
Mac Parker 1970
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.