===='Pesto' as test case====

{{>http://www.flickr.com/photos/foam/10454814174/}}

<graphviz dot right>

digraph G {
    bgcolor = "grey93";
    rankdir="LR";
    subgraph ingredients {
        graph [shape=circle];
        node [shape=circle];
        basil;
        "pine nuts";
        parmesan;
        garlic;
        "olive oil";
        intA;
        intB;
        pesto;
    }
    subgraph transitions {
        node [shape=rect];
        blend;
        grate;
        mix;
    }
    basil -> blend;
    garlic -> blend;
    "pine nuts" -> blend -> intA -> mix;
    parmesan -> grate -> intB -> mix;
    "olive oil" -> mix;
    mix -> pesto [label="until mixed"];
}

</graphviz>

NOTE: pre- and postconditions are not included above.