diff --git a/my_tree.py b/my_tree.py
index 823dbfc..456073d 100644
--- a/my_tree.py
+++ b/my_tree.py
@@ -9,7 +9,19 @@ w.bgcolor('wheat')      # wheat小麦
 # 移动到起点
 pen.left(90)
 pen.up()
-pen.backward(150)    # 后退
+pen.backward(750)    # 后退
 pen.down()
 
+def tree(n):
+   if n >= 50:
+       pen.forward(n)
+       pen.right(30)
+       tree(n-50)
+       pen.left(60)
+       tree(n-50)
+       pen.right(30)
+       pen.backward(n)
+       pen.down()
+
+tree(350)
 turtle.done()