2 chords - 2nd chord 3s & 4s cross to opp side
Note: after 2nd time through 1c may repeat [1-4] to get to 4pl.
On 2nd chord, 3c+4c change sides (to 1,2,3x,4x)
note: 3c does not move on bars 1-8.
Note: Cosh explicitly tells 1c to pass Lsh in [9-24]; however the Rsh pass is quite common, and nicknamed »Mairi's Divorce«.