save project

my_tree.py

 import turtle
-
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
@@ -13,15 +13,18 @@ pen.backward(150)    # 后退
 pen.down()
 
 def tree(n):
-    if n>=50:
+    if n>=0:
+        pen.pensize(n/10)
         pen.forward(n)
-        pen.right(30)
-        tree(n-50)
-        pen.left(60)
-        tree(n-50)
-        pen.right(30)
+        angle=random.randint(0,30)
+        length=random.randint(0,20)
+        pen.right(angle)
+        tree(n-length)
+        pen.left(2*angle)
+        tree(n-length)
+        pen.right(angle)
         pen.up()
         pen.backward(n)
         pen.down()
-tree(100)
+tree(50)
 turtle.done()