{{explanation}}
Start:	Dancers 1,2,3,4 in a line, 1 & 2 facing down, 3 & 4 facing up

1-8
: 1 & 3 set, Petronella turn to face across; 1s & 3s set, Petronella turn
  to have changed places.  3 2 1 4
9-16
: 2 & 1 set, Petronella turn to form diamond shape set; 2s+1s dance DoSiDo
17-24
: All dance R&L in Diamond:;

: 2+1 change places RH, 3+1 also 2+4 change places LH

: 3+4 change places RH, 1+4 also 3+2 change places LH (all are now
  opposite place at start of this figure)
25-28
: 1+2 turn 1.1/2 RH
29-32
: 1 dances to bottom of line **while** 2 dances to top **while** 4+3 turn
  LH to join RH with 1 & 2, all Bal-in-Line.  2 3 4 1