save project

my_tree.py

 import turtle
-
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
@@ -15,11 +15,13 @@ pen.down()
 def tree(n):
     if n>=10:
         pen.forward(n)
-        pen.right(30)
-        tree(n-10)   
-        pen.left(60)
-        tree(n-10)
-        pen.right(30)
+        angle=random.randint(0,30)
+        length=random.randint(1,15)
+        pen.right(angle)
+        tree(n-length)   
+        pen.left(2*angle)
+        tree(n-length)
+        pen.right(angle)
         pen.up()
         pen.backward(n)
         pen.down()