wolffd@0: digraph G {
wolffd@0: size="6,6";
wolffd@0: 	a -> b -> c;
wolffd@0: 
wolffd@0: 	subgraph cluster0 {
wolffd@0: 		x0 -> y0;
wolffd@0: 		x0 -> z0;
wolffd@0: 	}
wolffd@0: 
wolffd@0: 	subgraph cluster1 {
wolffd@0: 		x1 -> y1;
wolffd@0: 		x1 -> z1;
wolffd@0: 	}
wolffd@0: 
wolffd@0: 	subgraph cluster2 {
wolffd@0: 		x2 -> y2;
wolffd@0: 		x2 -> z2;
wolffd@0: 	}
wolffd@0: 
wolffd@0: 	a -> x0;
wolffd@0: 	b -> x1;
wolffd@0: 	b -> x2;
wolffd@0: 	a -> z2;
wolffd@0: 	c -> z1;
wolffd@0: }