save project

my_tree.py

 import turtle
-
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
+pen.speed(0)
 w = turtle.Screen()
 w.bgcolor('wheat')      # wheat小麦
 def tree(n):
-    if n>=50:
+    if n>=0:
+        if n<12:
+            pen.pencolor('snow')
+            pen.pensize(n/2)
+        else:
+            pen.pencolor('sienna')
+            pen.pensize(3)
+        lengh=random.randint(1,15)
+        angle=random.randint(10,30)
         pen.pendown()
         pen.forward(n)
-        pen.right(30)
-        tree(n-10)
-        pen.left(60)
-        tree(n-10)
-        pen.right(30)
+        pen.right(angle)
+        tree(n-lengh)
+        pen.left(2*angle)
+        tree(n-angle)
+        pen.right(angle)
         pen.backward(n)
         pen.penup()
 
@@ -21,5 +30,5 @@ pen.left(90)
 pen.up()
 pen.backward(150)    # 后退
 pen.down()
-tree(100)
+tree(80)
 turtle.done()