1digraph G { 2 3 subgraph cluster0 { //subgraph<Graph> 4 node [style=filled color=white]; 5 style = filled; 6 bgcolor = lightgrey; 7 8 subgraph inner { //subgraph<Graph> or subgraph of subgraph 9 node [color = green]; 10 a1 -> a2 -> a3 11 12 }; 13 14 a0 -> subgraph inner; 15 16 label = "process #1"; 17 } 18 19 subgraph cluster1 { 20 node [style=filled color=white]; 21 b0 -> b1 -> b2 -> b3; 22 label = "process #2"; 23 bgcolor = lightgrey 24 } 25 26 subgraph cluster1 -> subgraph cluster0 [style=dashed color=red] 27 28 start -> subgraph inner[style=dotted]; 29 30 start -> a0; 31 start -> b0; 32 a1 -> b3; 33 b2 -> a3; 34 a3 -> end; 35 b3 -> end; 36 37 start [shape=Mdiamond]; 38 end [shape=Msquare]; 39} 40