title: python turtle drawing is not visible, the window stays open but nothing appears on it
body: <p>I am learning python, I have started on a simple pong game. I have the code to draw two paddles on both sides of the screen the paddles don't appear just a blank screen in the output. Here is the code:</p>
  <blockquote>
  <pre><code>import turtle
  
  #creating a window for pong
  win = turtle.Screen()
  win.title(&quot;PONG&quot;)
  win.bgcolor(&quot;white&quot;)
  win.setup(width=800, height=600)
  win.tracer(0)
  
  
  
  #creating paddle A
  paddle_a = turtle.Turtle()
  paddle_a.speed(0)
  paddle_a.color(&quot;black&quot;)
  paddle_a.shape(&quot;square&quot;)
  paddle_a.shapesize(stretch_wid=5, stretch_len=1)
  paddle_a.penup()
  paddle_a.goto(-350,0)
  
  
  #creating paddle B
  paddle_b = turtle.Turtle()
  paddle_b.speed(0)
  paddle_b.color(&quot;black&quot;)
  paddle_b.shape(&quot;square&quot;)
  paddle_b.shapesize(stretch_wid=5, stretch_len=1)
  paddle_b.penup()
  paddle_b.goto(350,0)
  
  
  #ball
  ball = turtle.Turtle()
  ball.speed(0)
  ball.color(&quot;black&quot;)
  ball.shape(&quot;square&quot;)
  ball.penup()
  ball.goto(0,0)
  
  win.exitonclick()
  </code></pre>
  </blockquote>
  <p>PLEASE TELL ME WHERE I AM WRONG!!</p>