test_tree={
      axiom="FFFFFFFFA",
      rules_a="FFFFFFF[BBBB]A[-F][+F][+++F][+++++F]",
      rules_b="+[&&FF[&&--F][&&++F]]+",
      trunk="default:tree",
      leaves="default:leaves",
      angle=45,
      iterations=4,
      random_level=0,
  }