{{explanation}}
1s & 3s start on opp sides

1-8
: 1s also 4s in prom hold dance reel of 3 with 2s/3s (RSh to 2M/3M to
  start) & 1s+4s end in middle
9-16
: 1s+4s dance RH across, 1s & 4s change places with corner persons RH &
  set to them
17-24
: All dance 3/4 double diagonal reel of 4 giving LH in centre (end with 3s
  in 1st pl, 4s & 1s in middle & 2s in 4th pl opp sides)
25-32
: 4s+1s dance LH across **while** 3s+2s chase clockwise 1/2 way & all on
  sides set to partner & change places RH. (2)4(1)3