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

1-8
: 1s+2s also 3s+4s dance RH across, 1s & 4s cross RH & cast in 1 place
9-16
: 1s+4s dance LH across, 2s+1s also 4s+3s turn RH (4 bars) on sides to end
  with 2s & 4s facing down & 1s & 3s facing up
17-24
: All dance reels of 4 on sides (1s & 4s do not fully complete reel but
  turn right about to face other corner)
25-32
: 4s & 1s turn corners RH, 4s+1s dance LH across
33-40
: 4s & 1s dance up/down behind 2s/3s, cross RH & dance down/up behind
  2s/3s & cross RH. 2 4(1)(3)