quad_ex.dot

digraph G {
    0 [label=" "]
    sg1 [label="67"]
    sd1 [label="32"]
    ig1 [label=" "]
    id1 [label="7"]
    sg2 [label=" "]
    sd2 [label="2"]
    ig2 [label="1"]
    id2 [label=" "]
    sg3 [label="12"]
    sd3 [label="1"]
    ig3 [label="2"]
    id3 [label="3"]
    sg4 [label="8"]
    sd4 [label="4"]
    ig4 [label="5"]
    id4 [label="9"]
  0->{sg1, sd1, ig1, id1}
  ig1->{sg2, sd2, ig2, id2}
  sg2->{sg3, sd3, ig3, id3}
  id2->{sg4, sd4, ig4, id4}
}