save project

my_tree.py

 import turtle
+import random
+list=('snow',"lightcoral")
+def tree(n):
+    if n>=0:
+        pen.pensize(n/10)
+        pen.forward(n)
+        angle = random.randint(0,30)
+        length = random.randint(1,15)
+        pen.right(angle)
+        tree(n-length)
+        pen.left(2*angle)
+        tree(n-length)
+        pen.right(angle)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+        if n<=12:
+            pen.color(random.choice(list))
+            pen.pensize(n/3)
+        else:
+            pen.color("sienna")
+            pen.pensize(n/10)
 
 pen = turtle.Turtle()
 pen.color('sienna')
@@ -11,22 +33,10 @@ pen.left(90)
 pen.up()
 pen.backward(150)    # 后退
 pen.down()
-pen.pensize(8)
-
-pen.forward(150)
-pen.right(30)
-pen.forward(150)
-pen.up()
-pen.backward(150)
-pen.left(60)
-pen.down()
-pen.forward(150)
-pen.backward(150)
-pen.right(30)
-pen.backward(150)
-
-
+pen.pensize(2)
+pen.speed(0)
 
+tree(65)
 turtle.done()