digraph G {
  rankdir=LR;

  subgraph cluster_t0 {
    a [label="4"]
    b [label="5"]
    c [label="2"]
  }
  
  subgraph cluster_t1 {
    d [label="0"]
    e [label="9"]
  }

  subgraph cluster_t2 {
    f [label="8"]
    g [label="1"]
    h [label="4"]
  }

  a -> b;
  b -> c;
  c -> d [constraint=false];

  d -> e;
  e -> f [constraint=false];
  
  f -> g;
  g -> h;
}