1 digraph Unique {

     2   mindist = 2.0

     3   1 -> 2 [label="annotation"]

     4   1 -> 3 [label="selector"]

     5   2 -> 3 [label="selector"]

     6   3 -> 4 [label="field"]

     7   4 -> 4 [label="field"]

     8   1 [shape=circle, style=filled, color=blue]

     9   2 [shape=circle, style=filled, color=red]

    10   3 [shape=circle, style=filled, color=red]

    11   4 [shape=doublecircle, style=filled, color=green]

    12 }