diff --git a/my_tree.py b/my_tree.py
index 5e829ae..aeedfe4 100644
--- a/my_tree.py
+++ b/my_tree.py
@@ -1,5 +1,17 @@
 import turtle
 
+def tree(n):
+    if n>=0:
+        pen.forward(n)
+        pen.right(30)
+        tree(n-10)
+        pen.left(60)
+        tree(n-10)
+        pen.right(30)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
@@ -11,30 +23,5 @@ pen.left(90)
 pen.up()
 pen.backward(150)    # 后退
 pen.down()
-pen.forward(100)
-pen.right(30)
-pen.forward(50)
-pen.right(180)
-pen.forward(50)
-pen.right(120)
-pen.forward(50)
-pen.forward(-50)
-pen.right(30)
-pen.forward(-100)
-
-pen.forward(100)
-pen.right(30)
-pen.forward(50)
-pen.up()
-pen.backward(50)
-pen.down()
-pen.left(60)
-pen.forward(50)
-pen.up()
-pen.backward(50)
-pen.down()
-pen.right(30)
-pen.up()
-turtle.done()
-
+tree(60)
 turtle.done()