root
node1 (nt:unstructured)
a (nt:unstructured)
b (nt:unstructured)
node2 (nt:unstructured)
a (nt:unstructured)
b (nt:unstructured)
c (nt:unstructured) prop = "a"
node3 (nt:unstructured)
a (nt:unstructured)
b (nt:unstructured)
c (nt:unstructured) prop = "b"