{{explanation}}
3s and 4s start on opposite sides

1-8
: 1s+4s set & dance to opposite end of the set with Ladies casting & Men
  dancing in through middle passing RSh, all finishing facing up &
  down. 4s+2s also 3s+1s 1/2 turn RH on sides to finish facing person
  turned 2 (4) 1 (3)
9-24
: All dance parallel Celtic reels:

: All pass RSh, 4s & 1s chase 1/4 clockwise outside **while** 2s+3s
  dance 3/4 LH across to lines across

: Repeat 3 times changing orientation each 4 bars.

: Finish with 1s+4s retaining hold, joining RH with corners in a St
  Andrew's Cross
25-32
: All balance in line, 4s & 1s turn corners RH (4 bars) to finish in the
  sidelines & all set
33-40
: 4s+1s dance 1/2 Fig of 8 round nearest end couple & turn partner RH.
   2 4 (1) (3)