digraph G {
  node [ center 
  compound
  concentrate
  constraint
  decorate
  diredgeconstraints
  fixedsize
  headclip
  labelfloat
  landscape
  mosek
  nojustify
  normalize
  overlap
  pack
  pin
  regular
  remincross
  root
  splines
  tailclip
  truecolor
  ]
  "Bonn" -> "Berlin"

}
