From a completed double pass thru or eight chain thru formation: The couple in the center of the set angles apart to walk up and become ends of a line with the outside couple. Finishes in lines facing out or lines with ends facing out and centers facing in.
BACKGROUND NOTE: From double pass thru formation or eight chain thru, a similar move is called Outsides Out/In but it hasn't been specifically placed on the Mainstream List yet. Some other movements were experimented with for a time which involved the Centers In/Out--Outsides In/Out idea, but their names have been dropped in favor of the Mainstream term.
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.