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

1-4
: 1s & 4s set & cross down/up to next place **while** 2s & 3s cross RH &
  cast to ends
5-8
: 2s & 3s cross down/up & cast to ends **while** 1s & 4s cast to ends &
  cross LH down/up to next place.  2 1 (4)(3)
9-16
: All dance Grand Chain
17-24
: 1s+4s set, dance RH across 1/2 way, 4s+1s circle 4H round to left
25-32
: 4s+1s set & 1/2 turn partners, lead up/ between end couples, cross &
  cast in 1 place.  2 4 (1)(3)