save project

my_tree.py

 import turtle
-
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
@@ -11,5 +11,16 @@ pen.left(90)
 pen.up()
 pen.backward(150)    # 后退
 pen.down()
-
+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.penup()
+        pen.backward(n)
+        pen.pendown()
+tree(60)
 turtle.done()