save project

my_tree.py

 import turtle
+import random
 
-pen = turtle.Turtle()
-pen.color('sienna')
+a = turtle.Turtle()
+a.speed(0)
+a.color('sienna')
 # 画布大小
 w = turtle.Screen()
 w.bgcolor('wheat')      # wheat小麦
 
+def tree(n):
+    if n>=0:
+        a.forward(n)
+        a.pensize(n/10)
+        b=random.randint(0,30)
+        c=random.randint(0,10)
+        a.right(b)
+        tree(n-c)
+        a.left(b*2)
+        
+        tree(n-c)
+        a.right(b)
+        a.penup()
+        a.backward(n)
+        a.down()
+
 # 移动到起点
-pen.left(90)
-pen.up()
-pen.backward(150)    # 后退
-pen.down()
+a.left(90)
+a.penup()
+a.backward(150)    # 后退
+a.down()
+
+a.forward(100)
+
+tree(60)
+a.penup()
+a.backward(100)
+a.pendown()
+
+
 
 turtle.done()