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

1-8
: 1s set & 1/2 turn into prom hold facing 2M **while** 4s set & 1/2 turn
  to face 3M in prom hold, 1s & 4s dance 1/2 RSh reels of 3 across set
9-16
: 1s dance 1/2 reel of 3 on Ladies' side **while** 4s dance 1/2 reel on
  Men's side. Still in prom hold 1s+4s dance once round each other RSh &
  to face corner persons (4s face 3s at top & 1s face 2s Man facing Man,
  Lady facing Lady)
17-28
: 1s & 4s set to corners, set facing partner, repeat twice more
29-32
: 1s+4s dance 3/4 LH across to end 3 1 (4) (2)