1 _:b1 <http://example.org/base#a> <http://example.org/base#b> .
2 _:b1 <http://example.org/base#c> <http://example.org/base#d> .
3 <http://example.org/base#e> <http://example.org/base#f> _:b2 .
4 _:b2 <http://example.org/base#g> <http://example.org/base#h> .
