digraph sentence {
np1 [label="NP"];
np2 [label="NP"];
np3 [label="NP"];
n1 [label="N"];
n2 [label="N"];
n3 [label="N"];
pp1 [label="PP"];
pp2 [label="PP"];
p1 [label="P"];
ap [label="AP"];
a [label="A"];
        VT -> np1 -> n1;
                np1 -> pp1 -> p1;
                        pp1 -> np2 -> ap -> a;
                                np2 -> n2;
        VT -> T -> past;
        VT -> VP -> V;
                VP -> pp2 -> P;
                        pp2 -> np3 -> D;
                                np3 -> n3;
}