chart_intro_prodedge.dot

digraph x {
   rankdir=LR;
   ranksep=0.25;

   /* The nodes */
   {
       node [style=filled,height=0.1,width=0.1,fillcolor=cadetblue4];
       0 [label=""];
       1 [label=""];
       2 [label=""];
       3 [label=""];
   }

   /* The sentence */
   {
       edge [style=invis, weight=100];
       node [shape=plaintext,fontname="Times-BoldItalic"];
       0->John->1->likes->2->Mary->3;
   }
   
   /* Edges */
   {
       edge [fontname=LucidaGrande];
       1->3 [label="VP → V NP"];
       1->2 [label="V  → likes"];
       2->3 [label="NP → Mary"];
   }

}