From a squared set: Number one couple walks across the set to do a centers in with the No. 3 couple and then U-turn back. This forces the other six dancers to slide to their left or right 1/8 of a position to re-form a new squared set. All dancers now assume the new position number. The new No. 1 now repeats the action and the other dancers slide 1/8 to re-form the square, etc.
Dan Allen and Madeleine Allen 1955
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.