digraph {
  rankdir=LR;
  bgcolor=transparent;
  node [shape="box", style="filled,rounded",fontname="sans-serif", fixedsize=true,width=2.5];

  a [fillcolor="#ff000077",label="FileDataObject"];
  b [fillcolor="#ff000077",label="FileDataObject"];
  c [fillcolor="#ff000077",label="Attachment"];
  d [fillcolor="#ff000077",label="EmbeddedFileDataObject"];

  a2 [fillcolor="#00ff0077",label="Folder"];
  b2 [fillcolor="#00ff0077",label="Document"];
  c2 [fillcolor="#00ff0077",label="Archive"];
  d2 [fillcolor="#00ff0077",label="Photo"];

  subgraph cluster_do {
    color=transparent;
    label = "DataObject";
    fontname="sans-serif";
    fontsize=10;
    a;
    b;
    c;
    d;
  }

  subgraph cluster_ie {
    color=transparent;
    label = "InformationElement";
    fontname="sans-serif";
    fontsize=10;
    a2;
    b2;
    c2;
    d2;
  }

  a -> a2 [color="#777777ff",dir=back];
  a2 -> b:ne [color="#777777ff",dir=back];
  b -> b2 [color="#777777ff",dir=back];
  b2 -> c:ne [color="#777777ff",dir=back];
  c -> c2 [color="#777777ff",dir=back];
  c2 -> d:ne [color="#777777ff",dir=back];
  d -> d2 [color="#777777ff",dir=back];
}