1<?xml version="1.0"?> 2<docs> 3 <doc1> 4 <a level="1" origin="house">1a1</a> 5 <a level="1" origin="Albany">1a2</a> 6 <doc1supplement> 7 <a level="1" origin="Austin">1xa1</a> 8 </doc1supplement> 9 </doc1> 10 <doc2> 11 <a level="2" origin="Baltimore">2a1</a> 12 <b level="2" origin="Albany">2b1</b> 13 <a level="2" origin="Portland">2a2</a> 14 <a level="2" origin="Albany">2a3</a> 15 <doc2supplement> 16 <a level="3" origin="Chicago">2xa1</a> 17 <a level="3" origin="Albany">2xa2</a> 18 <a level="3" origin="Albany">2xa3</a> 19 <d level="3" origin="Albany">2xd1</d> 20 </doc2supplement> 21 </doc2> 22</docs>