digraph {
   rankdir = LR;
   newrank = true;
   dpi = 300.0;
   
   node [shape = "plaintext";];
   
   
   subgraph cluster_not_fut {
      peripheries = 0;
      
      pin [label = <<table border="0" cellborder="1" cellspacing="0">
         <tr><td sides="B">Pin</td></tr>
         <tr><td port="source"> </td></tr>
         </table>>;];
      
      subgraph cluster_boxes {
         peripheries = 0;
         rank = same;
         
         subgraph cluster_box_1 {
            subgraph cluster_box_2_internal {
               label = "b1";
               shape = box;
               style = solid;
               style = filled;
               peripheries = 1;
               box1 [shape = "point";style = "invis";];
            }
         }
         
         subgraph cluster_box_2 {
            subgraph cluster_box_2_internal {
               label = "b2";
               shape = box;
               style = solid;
               peripheries = 1;
               box2 [shape = "point";];
            }
         }
      }
   }
   subgraph cluster_target {
      style = bold;
      label = "pinned";
      
      fut [label = <<table border="0" cellborder="1" cellspacing="0">
         <tr><td sides="B">fut</td></tr>
         <tr><td port="target">0</td></tr>
         <tr><td port="source"> </td></tr>
         <tr><td style="dashed">...</td></tr>
         <tr><td port="internal">1</td></tr>
         </table>>;];
   }
   
   
   box1 -> box2 [rankdir = TB; style = invis;];
   
   edge [tailclip = false;];
   pin -> box1 [style = "invis";];
   pin -> box2 [tailport = "source:c"; arrowhead = "none";];
   box2 -> fut [headport = "target";];
   fut -> fut [tailport = "source:c"; headport = "internal";];
}