gistfile1.txt

  splines=line
  node [shape=circle style=""]
  node [group=master]
  d -> c -> b -> a;
  node [group=brancha]
  h -> g -> f -> e -> b;
  node [group=branchb] 
  k -> j -> i -> g;

  node [group=""]
  c -> h;
  d -> k;


  node [shape=box style=filled fillcolor=green];
  brancha[label="branch A"]
  branchb[label="branch B"]
  {rank=same master -> d}
  {rank=same brancha -> h}
  {rank=same branchb -> k}