1  #
 2  # purchaseOrder
 3  #
 4  t 0 1 shipTo
 5  t 1 2 billTo
 6  t 2 3 comment
 7  t 3 4 items
 8  e 2 3
 9  f 4
10  -------
11  shipTo
12  billTo
13  comment
14  items
15  =>
16  shipTo
17  billTo
18  items
19  =>