{{explanation}}
On 2nd chord 3c+4c change sides to 1,2,3x,4x. Centro-symmetrical dance.

1–
: 2c+3c Petronella Turn and set ; turn ¾ RH into ½RHA to form pairs in promhold facing out (3W+2M on M side ; 2W+3M on W side).
9–
: 1c+4c Petronella Turn | set ; ½ RH turn and Promenade clw to the side positions, forming a square set **while**{8} the pairs cast R | pass between end Cs ; Promenade clw to other end
17–
: 1c+4c ½ L-Chain across ; the pairs ½ M-Chain, finishing with a full RH turn to put M on the right of P (2c at top, 3c at bottom)
25–
: All set | ½ circle8 L {3}, dance in on L foot into centre and all swivel R {1} | spiral out into longwise set (2,4,1x,3x)