generators.ET0LTreeGrammar:
(
  { S, A, B },
  { tile:0, tile2:0, tile3:0, refine:9, refine2:3, refine3:3 },
  {
    {
      S -> refine[S,A,A,A,A,A,A,A,A],
      A -> refine2[B,B,B],
      B -> refine3[B,B,B]
    },
    {
      S -> tile,
      A -> tile2,
      B -> tile3
    }
  },
  S
)
