auto save

my_tree.py

 import turtle
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 pen.speed(0)
@@ -7,15 +8,26 @@ w = turtle.Screen()
 w.bgcolor('wheat')
 def tree(n):
     if n>0:
+        if n<12:
+            c_list=['snow','lightcoral']
+            o=random.choice(c_list)
+            pen.color(o)
+            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-10)
-        pen.right(30)
+        a=random.randint(0,30)
+        b=random.randint(1,15)       
+        pen.right(a)
+        tree(n-b)
+        pen.left(2*a)
+        tree(n-b)
+        pen.right(a)
         pen.up()
         pen.backward(n)
         pen.down()
+
       # wheat小麦
 
 # 移动到起点