The biconnected graph 
on seven nodes and seven edges illustrated above. It
has chromatic polynomial
 |
and chromatic number 
.
The puz-graph of a finite simple biconnected
graph 
that is not polygonal always has two connected
components if 
is bipartite; otherwise (with the exception of
), 
is connected. Surprisingly,
the puz-graph of the 
graph is the sole exception, having six connected
components instead of a single component.
