AquĆ unos Samples.
<graphviz> digraph test { this [shape=doublecircle]; is [shape=box]; a [shape=invtriangle]; test [shape=polygon,sides=6,color=red,style=filled]; { rank = same; this; what; } this->is; is->a; a->test; test->what; what->do; do->you; you->"think?"; } </graphviz>