digraph {
  splines=true;
  node [shape=octagon penwidth=7]

  // Ensure node obstacles don't overlap in order to avoid:
  // "Warning: some nodes with margin (3.20,3.20) touch - falling back to straight line edges"
  // in which case splines will not be used
  edge [len=1.6]

  node1 -> node2:sw;
  node1 -> node2:ne;
}
