save project

my_tree.py

 import turtle
+import random
 
 pen = turtle.Turtle()
 pen.color('sienna')
@@ -12,13 +13,23 @@ pen.up()
 pen.backward(150)    # 后退
 pen.down()
 def tree(n):
-    if n>=30:
+    if n>=0:
+        if n <=12:
+            color_list=['snow','lightcoral']
+            color=random.choice(color_list)
+            pen._color(color)
+            pen.pensize(n/3)
+        else:
+            pen.color('sienna')
+            pen.pensize(n/10)
         pen.forward(n)
-        pen.right(30)
-        tree(n-10)
-        pen.left(60)
-        tree(n-510)
-        pen.right(30)
+        angle=random.random()
+        pen.right(30*angle)
+        length=1.5*random.random()
+        tree(n-10*length)
+        pen.left(60*angle)
+        tree(n-10*length)
+        pen.right(30*angle)
         pen.up()
         pen.backward(n)
         pen.down()