digraph {
  nd_0001 [
    shape=none
    
  label="A"
  ];

  nd_0002 [
    shape=none
    
  label="B"
  ];

  nd_0003 [
    shape=none
    
  label="C"
  ];

  nd_0004 [
    shape=none
    
  label="D"
  ];

  nd_0005 [
    shape=none
    
  label="E"
  ];

  nd_0006 [
    shape=none
    
  label="F"
  ];

nd_0001 -> nd_0002;
nd_0002 -> nd_0003;
nd_0006 -> nd_0005;
nd_0005 -> nd_0004;
  {rank=same; nd_0002 nd_0003 nd_0004}
  {rank=same; nd_0001 nd_0006}
}