1–
: 1c lead down the middle and loop up into 4pl (2c+3c+4c up on [3–4]) ; all set | Circle8 L for two places
9–
: All M (at top) LHA **while{4}** all W (below) RHA ; Continue both HA, but as each couple meets (order 1,4,3,2) they cross to the other wheel (W pass in front)
17–
: As couples meet again the W join RH with P, the M dancing as if still in RHA, and (1c leading) unwind and lead up the middle and out to opposite sidelines {6} | all turn P RH ½ into
25–
: 1c+4c+3c+2c Allemande (to 2,3,4,1)

{{explanation}}
“Easier version” for [17–20]: As couples meet the W join NH with P who maintain RHA (continue as described)