generators.ET0LTreeGrammar:
( { S, A },
  { init:1, F:1, G:3, part:0, set:1, inc:1, r0:1, r1:1, g0:1, g1:1, b0:1, b1:1 },
  {
    {
      S -> G[A,S,S] weight 2,
      S -> S
    },
    {
      S -> A,
      A -> r0[A], A -> r1[A],
      A -> g0[A], A -> g1[A],
      A -> b0[A], A -> b1[A]
    },
    {
      A -> F[inc[A]]
    },
    {
      S -> part,
      A -> part
    }
  },
  set[init[S]],
%  1* 2* 3* 4
  1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 (3 3 3 3 3 3 3 3)* 4
)
