auto save

my_tree.py

 import turtle
-
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
@@ -9,22 +9,29 @@ w.bgcolor('wheat')      # wheat小麦
 # 移动到起点
 pen.left(90)
 pen.up()
-pen.backward(150)    # 后退
-pen.down()
-
-#画树杈
-pen.fd(100)
-pen.right(30)
-pen.fd(50)
-pen.up()
-pen.backward(50)
+pen.backward(300)    # 后退
 pen.down()
-pen.left(60)
-pen.fd(50)
-pen.up()
-pen.backward(50)
-pen.right(30)
-pen.backward(100)
-pen.down()
-
+def tree(n):
+    if n >0:
+        if n <= 12:
+            color = ['snow','lightcoral']
+            pen.pencolor(random.choice(color))
+            pen.pensize(n/3)
+        else:
+            pen.pencolor('sienna')
+            pen.pensize(n/10)
+        angle = random.randint(0,30)
+        length = random.randint(1,15)
+        #画树杈
+        pen.fd(n)
+        pen.right(angle)
+        tree(n-length)
+        pen.left(2*angle)
+        tree(n-length)
+        pen.right(angle)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+turtle.tracer(False)  #不展示绘图过程
+tree(80)
 turtle.done()