Note on [27-28]: originally 2 PdB. modified by Drewry to SkCh. O. Otto says best variant is corners in PdB, 1c in SkCh
note: 3c does not move on bars 1-8.
Note that both times the couple moving UP makes the arch.
Note: Cosh explicitly tells 1c to pass Lsh in [9-24]; however the Rsh pass is quite common, and nicknamed »Mairi's Divorce«.