{{explanation}}
3s & 4s start on opp sides

1-8
: All dance Grand Chain starting on sides (ie 1s with 2s & 3s with 4s)

: Bar 8: 1s & 4s do not pass LH but take prom hold, 1s facing Ladies'
  side, 4s facing Men's side (Lady on Man's right), 2s face up, 3s face
  down
9-16
: 1s in prom hold dance reel of 3 with 2s (LSh to 2L) **while** 4s reel
  of 3 with 3s (LSh to 3L), ending in lines of 4 across (1s & 4s in
  centre of lines)
17-24
: All set, 1s+4s dance RH across once round, 1s & 4s dance up/down
  between 2s/3s to ends & turn to face 2s+3s (who dance in to face them)
25-28
: 1s+2s & 3s+4s set passing opp couple LSh 2s & 3s turn partners 2H
  as 1s+4s set passing LSh to 2 4 (1) (3)
29-32
: 2s+4s & 1s+3s circle 4H round to left.  2 4 (1) (3)