Each time through the dance the set is on a new axis perpendicular to the one before; the top of the set (Left end for the Men) rotates clockwise 1/4 of the way around (so top of hall, right-file wall, bottom of hall, left-file wall). However, the order of the active couples is 1, 4, 2, 3; as the couple at the bottom of the set is the new active couple on second and fourth time around.
Original:
1-8 Ones lead down the middle and back and cast into 2nd place
9-12 Partners R-hand turn once round
13-16 Partners dance back to back
17-24 Top and bottom foursomes dance R-hands across and L-hands across
25-30 Ends chase orbiting counterclockwise 3/4 round the set while middle four dance R-hands across 1 1/4 (5 places) to face partners
31-32 All set in lines of four on new axis
Repeat with new actives