save project

my_tree.py

 import turtle
+def tree(n):
+    if n>=50:
+        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')
@@ -11,13 +22,7 @@ pen.left(90)
 pen.up()
 pen.backward(150)    # 后退
 pen.down()
-pen.forward(100)
-pen.left(30)
-pen.forward(50)
-pen.backward(50)
-pen.right(60)
-pen.forward(50)
-pen.backward(50)
-pen.left(30)
-pen.backward(100)
+
+tree(100)
+    
 turtle.done()