{{explanation}}
3s+4s start on opposite sides

1-8
: 1s+4s petronella into centre & set to partners (2s+3s step up/down), 1s
  pass partner LSh, dance RSh round 2s (1L/2M, 1M/2L) as 4s dance
  similar round 3s
9-16
: 1s+4s dance 1/2 RSh reel of 4, All couples petronella 1 place right and
  set (2s+3s in centre facing prtnr, 4s in 1st place opp sides, 1s in
  4th place own side)
17-20
: 2s+3s turn RH, 2L/3L dance RSh round 4M/1M as 2M+3M turn 3/4 LH to face
  out on sides
21-24
: 2s+3s dance 1/2 Ladies' Chain (4) 3 (2) 1
25-30
: 4s+1s cross RH, cast up/down (3s+2s step up/down on 27-28), 4s+1s dance
  1/2 RH across
31-32
: All 4 couples set 3 1 (4) (2)