1 digraph G { 2 node [ shape=box ]; 3 rankdir=TD; 4 compound=true; 5 6 subgraph cluster { 7 label="Train"; 8 style="dashed"; 9 A [ label="Chassis" ]; 10 B [ label="Chamber" ]; 11 C [ label="Cabin" ]; 12 D [ label="Axes" ] 13 E [ label="Wheels" ] 14 F [ label="Cylinders" ] 15 G [ label="Floor" ] 16 H [ label="Cranks" ] 17 } 18 19 A -> {B, C, D, F, G, H}; 20 D -> E; 21 }