{{explanation}}
2s & 4s start on opposite sides

1-8
: All set, cross RH; set & turn partner 3/4 RH into Promenade hold (1s &
  3s face Ladies' side, 2s & 4s face Men's side
9-10
: 1s+2s also 3s+4s change places dancing around each other passing RSh
11-12
: 1s+4s change places dancing around each other passing LSh
13-14
: 2s+4s also 1s+3s change places dancing around each other passing RSh
15-16
: 4s+1s change places dancing around each other passing LSh **while**

: 2s+3s face partner facing up/down. 2s+3s separate from partner, 2s dance
  to 1st place own side, 3s dance to 4th place opp sides
17-24
: 2s+4s (in prom hold) also 3s+1s (in prom hold) dance reels of 3 across
  the dance. 4s pass 2M RSh, 1s pass 3M RSh to begin. 1s & 4s end in
  line on 1st corner diagonal with ladies BtoB
25-32
: 4s+1s dance All Round Poussette