title: When I press a key, all the other previously moving elements stop moving in python turtle
body: <p>So I'm making a 2 player tron game in turtle, and my code seemed to be working fine (except the border that's why I commented it out). The only thing is that when I tried to play the game by myself to test it out, whenever I moved the &quot;other&quot; tron bike, the one that I just had clicked to make move stops moving. How can I fix this?</p>
  <p>Here is my code:</p>
  <pre class="lang-py prettyprint-override"><code>def tron():
      #Drawing the starting turtles
      blueplayer = turtle.Turtle()
      redplayer = turtle.Turtle()
      screen = turtle.Screen()
      screen.setup(width, height)
      screen.bgpic('TronBg.png')
      screen.bgcolor('black')
      screen.addshape('BlueBike.gif')
      screen.addshape('RedBike.gif')
      blueplayer.shape('BlueBike.gif')
      redplayer.shape('RedBike.gif')
      redplayer.pencolor(&quot;red&quot;)
      redplayer.pensize(3)
      blueplayer.pencolor(&quot;blue&quot;)
      blueplayer.pensize(3)
      redplayer.pu()
      blueplayer.pu()
      redplayer.goto(width/2, height/8)
      blueplayer.goto(-1*(width)/2, height/8)
      redplayer.pd()
      blueplayer.pd()
  
      #Border
      #box = Turtle()
      #box.ht()
      #box.color('purple')
      #box.speed('fastest')
      #box.pensize(10)
  
     # box.pu()
     # box.goto(-1*height, -1*width)
     # box.pd()
  
     # for i in range(4):
     #   box.forward(height)
     #   box.left(90)
     #   box.forward(width)
     #   box.left(90)
        
      #Player movements
      def RedUp():
        while True:
          blueplayer.setheading(90)
          blueplayer.forward(3)
      def BlueUp():
        while True:
          redplayer.setheading(90)
          redplayer.forward(3)
  
      def RedDown():
        while True:
          blueplayer.setheading(270)
          blueplayer.forward(3)
      def BlueDown():
        while True:
          redplayer.setheading(270)
          redplayer.forward(3)
  
      def RedLeft():
        while True:
          blueplayer.setheading(180)
          blueplayer.forward(3)
      def BlueLeft():
        while True:
          redplayer.setheading(180)
          redplayer.forward(3)
  
      def RedRight():
        while True:
          blueplayer.setheading(0)
          blueplayer.forward(3)
      def BlueRight():
        while True:
          redplayer.setheading(0)
          redplayer.forward(3)
  
      for x in range(10):
        turtle.color('white')
        style = ('Arial', 25, 'italic')
        turtle.write(10-x, font=style, align='center') 
        time.sleep(1)
        turtle.undo()
    
      screen.listen()
  
      screen.onkey(RedUp, &quot;w&quot;)
      screen.onkey(RedDown, &quot;s&quot;)
      screen.onkey(RedLeft, &quot;a&quot;)
      screen.onkey(RedRight, &quot;d&quot;)
  
      screen.onkey(BlueUp, &quot;Up&quot;)
      screen.onkey(BlueDown, &quot;Down&quot;)
      screen.onkey(BlueLeft, &quot;Left&quot;)
      screen.onkey(BlueRight, &quot;Right&quot;)
      
      screen.mainloop()
  
  tron()
  </code></pre>