save project

my_tree.py

 import turtle
+import random
 
 pen = turtle.Turtle()
 pen.color('sienna')
@@ -11,5 +12,26 @@ pen.left(90)
 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*length)
+        pen.left(60*angle)
+        tree(n-10*length)
+        pen.right(30*angle)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+tree(60)
 turtle.done()