dot:
  graph: |
    graph [splines=true, nodesep=0.25, ranksep="1 equally"]
    //graph [splines=ortho, nodesep=0.2, ranksep="0.5 equally"]
    //node [color=white]
    //edge [headport=n, tailport=s]
    compound=true
    center=true
  subgraph:
    block: |
      labeljust=l
    hidden: |
      //rank=same
      //style=invis
  node:
    text: |
      shape=plaintext
    hidden: |
      //style=invis
      shape=point
      width=0
      height=0
  edge:
    default: |
      //headport=n
      //tailport=s
    hidden: |
      style=invis