{{explanation}}
Note: "Petronella-to-Left": 4 PdeB steps going diagonally forward to Left & turning 3/4 round to Left on 2nd/3rd steps

1-8
: 1s Petronella turn & set (2s step up); 1s turn 3/4 LH back to original
  places & set **while** 2s Petronella turn & set (1M now facing 2L, 2M
  facing 1L)
9-16
: 1L & 2M stand (4 bars) **while** 2L dances Petronella turn & 1M, dancing
  in front of 2L, dances Petronella-to-Left (1M & 2L have changed
  places); All dance RH across once round
17-24
: 1M+2M Petronella turn & set **while** 1L & 2L, going inside them,
  Petronella-to-Left; all dance LH across once round
25-32
: 1L dances anticlockwise round others to 2nd place own side (8 bars) as
  1M dances Petronella turn & follows partner 2nd place own
  side **while**

: 2L stands (2 bars), dances Petronella turn, dances anticlockwise round
  to 1st place own side as 2M stands (4 bars), dances Petronella turn &
  follows 1M to end in 1st place own side