generators.ET0LTreeGrammar("iterated Koch island"):
( { S0, S, S1 },
  { F0:4, F:8, G:9, sq:0, -:0 },
  {
    {
      S0 -> F0[S1,S1,S1,S1],
      S1 -> G[S1,S,S,S,S,S,S,S,S],
      S -> F[S,S,S,S,S,S,S,S]
    },
    {
      S0 -> sq,
      S1 -> sq,
      S -> sq
    }
  },
  S0
)
