生成规则：以如图8-27n＝2所示二叉树为基础，以每个分支为主树干，按照比例递归出另一个二叉树，如图8-27n＝3所示。依此类推，便形成了疏密有致的分形树，称为Caley树-Generated rules: in Figure 8-27n = 2 as shown is based on binary tree to each branch of the main trunk, in accordance with the proportion of another recursive bina