{{explanation}}
3rd and 4th couples start on opposite side: (1,2,3x,4x).

1–
: All set | turn BH opening into ; 1c+2c & 3c+4c, circle4 L to places
9–
: 1M+2W+3W+4M ½ Rsh diag. Reel4 (2W & 3W start towards own end and return straight to own places) ; 1W+2M+3M+4W ½ Rsh diag. Reel4 (2M & 3M start towards own end and return straight to own places) (4,2,3x,1x)
17–
: 4c+2c & 3c+1c, R&L starting up/down, finish NHJ facing the other couple
25–
: 4c+2c & 3c+1c Rondel ‑ 2c & 3c making the arches (to 2,4,1x,3x)