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

1-8
: 1L+4L dance RSh round partner, face partner, pull back RSh (twirl) to
  face own sides **while** 1M+4M stand still for 2 bars, set. 1s+4s
  (Lady leading) chase 1/2 way clockwise to change places. 4L+1L face
  out 4 2 (3) (1)
9-16
: 4s+2s+3s+1s dance RSh reel of 4 on the sides. 2M+3M end facing out
17-24
: 2s+3s dance a Ladies' chain
25-28
: All set, turn partner 3/4 RH to line up/down centre
29-36
: 4s+2s also 3s+1s dance half Celtic reels:

: **29-32**  4s+2s (3s+1s) pass partners RSh, 4M+2L (3L+1M) dance
  clockwise 1/4 way **while** 4L+2M (3M+1L) dance 3/4 LSh round each
  other to face partners in lines across the set

: **33-36**  4s+2s (3s+1s) pass partners RSh, 4L+2M (3M+1L) dance
  clockwise 1/4 way **while** 4M+2L (3L+1M) dance 3/4 LSh round each
  other to face partners in line up/down
37-40
: All turn partners 3/4 RH to finish on the sides & all set 2 4 (1) (3)