save project

my_tree.py

 import turtle
+import random
 
 pen = turtle.Turtle()
 pen.color('sienna')
@@ -12,4 +13,32 @@ pen.up()
 pen.backward(150)    # 后退
 pen.down()
 
+def tree(n):
+    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)
+        angle = random.random()
+        pen.right(30*angle)
+        length = 1.5*random.random()
+        tree(n-10*lengle)
+        pen.left(60*angle) 
+        tree(n-10*length)
+        pen.right(30*angle)
+        pen.right(30)
+        tree(n-10)
+        pen.reft(60)
+        tree(n-10)
+        pen.right(30)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+        
+tree(100)
 turtle.done()