generators.ET0LTreeGrammar:
(
  { S, S+ },
  { background:0, .:2, 45-deg:9, full:8, shrink:1, shrink+:1, p:0, col:1 },
  {
    {
      S -> shrink[col[S+]],
      S+ -> shrink+[col[S]]
    },
    {
      S -> p,
      S+ -> p
    }
  },
  (background .
  full[45-deg[S+,S,S+,S,S+,S,S+,S,S+],
       45-deg[S,S+,S,S+,S,S+,S,S+,S],
       45-deg[S+,S,S+,S,S+,S,S+,S,S+],
       45-deg[S,S+,S,S+,S,S+,S,S+,S],
       45-deg[S+,S,S+,S,S+,S,S+,S,S+],
       45-deg[S,S+,S,S+,S,S+,S,S+,S],
       45-deg[S+,S,S+,S,S+,S,S+,S,S+],
       45-deg[S,S+,S,S+,S,S+,S,S+,S]])
)
