boost_1_45_0/libs/graph/doc/figs/biconnected.dot

graph A {
  node[shape="circle"]
B [ style="filled", fillcolor="red" ];
G [ style="filled", fillcolor="red" ];
A [ style="filled", fillcolor="red" ];
A -- F[label="1"]
A -- B[label="1"]
A -- G[label="3"]
B -- C[label="0"]
B -- D[label="0"]
B -- E[label="1"]
C -- D[label="0"]
E -- F[label="1"]
G -- I[label="2"]
G -- H[label="2"]
H -- I[label="2"]
}