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

1-8
: 1s & 4s set & cast in 1 place, cross RH & cast to ends to form lines
  across (1s between 2s & 4s between 3s)
9-16
: 1s+2s also 3s+4s Adv+Ret up/down, 1s+4s dance 1/2 R&L **while** others
  turn RH on sides, all now in square set & facing corners
17-24
: All set HS to corners & all turn corners 2H twice to end on sidelines
25-32
: All set to partners, 4s+2s also 3s+1s dance 3/4 Fig of 8 (end couples
  cast to start) to end 2 4 (1) (3)