1 digraph Union {

     2   mindist = 2.0

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

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

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

     6   3 -> 3 [label="simpleType"]

     7   1 [shape=doublecircle, style=filled, color=blue]

     8   2 [shape=doublecircle, style=filled, color=green]

     9   3 [shape=doublecircle, style=filled, color=green]

    10 }