From two parallel waves: Ends arm turn adjacent dancer 3/4, new centers Trade then arm turn new ends 3/4. Finishes in two parallel waves.
COMMENT: This move is part of an older call "Swing The Square" by Ed Hall, Meadville, PA. In Swing the Square, from parallel waves, Ends arm turn 3/4, new centers arm turn half, ends arm turn 3/4, new centers arm turn half, etc. until all dancers have returned to original positions in original waves.
NOTE: The first two moves of this go under the name of Three Quarter Thru which is a term on the Challenge Dancing's Basic Calls list.
After Chain The Line, several other names were given to this same or closely similar moves as follows:
See Cast Chain Thru, Grand Chain Thru, Spinning Wheel, Split The Difference.