This may not be a complete list of all calls authored by Bill Colby.
Jay King - page 59
Heads Part: Fan the Top, step thru to the side position. Do a partner trade and roll. Back away four steps and turn to face the head position. Walk forward to the head position and slide thru with the one they meet.
Sides Part: Face partner and back away four steps to turn and face the head position. Walk forward to the head position and Slide Thru. Go into the center and Fan the Top, then step thru to the side position. Do a partner trade and roll.
All do the above routine twice thru to return to original home with partners.
Bill Colby 1968
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.