1 digraph G {

     2     compound=true;

     3     rankdir=LR;

     4 

     5     subgraph cluster0 {

     6         label = "Network";

     7 	{rank=source; client; server;}

     8 	client;

     9 	server;	

    10 	color = black;

    11     }

    12 

    13     subgraph cluster1 {

    14         label = "Game Engine";

    15 	{rank=min; gs; physics; interpolation; }

    16 	gs;

    17 	physics;

    18 	interpolation;

    19 	color = black;

    20     }

    21 

    22     {rank=sink; input; graphics;}

    23     client->server;

    24     server->client;

    25 

    26     gs->physics;	

    27     physics->interpolation;

    28 

    29     input->interpolation;

    30     input->client;

    31     interpolation->graphics;

    32 

    33     server->gs;

    34     gs->client;

    35 }