title: How to put text on the widget
body: <p>I am using the following code to gain an understanding in developing apps. However how do I put a custom text on the ball:</p>
  
  <pre><code>class PongPaddle(Widget):
      score = NumericProperty(0)
  
      def bounce_ball(self, ball):
          if self.collide_widget(ball):
              vx, vy = ball.velocity
              offset = (ball.center_y - self.center_y) / (self.height / 2)
              bounced = Vector(-1 * vx, vy)
              vel = bounced * 1.1
              ball.velocity = vel.x, vel.y + offset
  
  
  class PongBall(Widget):
      velocity_x = NumericProperty(0)
      velocity_y = NumericProperty(0)
      velocity = ReferenceListProperty(velocity_x, velocity_y)
  
      def move(self):
          self.pos = Vector(*self.velocity) + self.pos
  
  
  class PongGame(Widget):
      ball = ObjectProperty(None)
      player1 = ObjectProperty(None)
      player2 = ObjectProperty(None)
  
      def serve_ball(self, vel=(4, 0)):
          self.ball.center = self.center
          self.ball.velocity = vel
  
      def update(self, dt):
          self.ball.move()
  
          # bounce of paddles
          self.player1.bounce_ball(self.ball)
          self.player2.bounce_ball(self.ball)
  
          # bounce ball off bottom or top
          if (self.ball.y &lt; self.y) or (self.ball.top &gt; self.top):
              self.ball.velocity_y *= -1
  
          # went of to a side to score point?
          if self.ball.x &lt; self.x:
              self.player2.score += 1
              self.serve_ball(vel=(4, 0))
          if self.ball.x &gt; self.width:
              self.player1.score += 1
              self.serve_ball(vel=(-4, 0))
  
      def on_touch_move(self, touch):
          if touch.x &lt; self.width / 3:
              self.player1.center_y = touch.y
          if touch.x &gt; self.width - self.width / 3:
              self.player2.center_y = touch.y
  
  
  class PongApp(App):
      def build(self):
          game = PongGame()
          game.serve_ball()
          Clock.schedule_interval(game.update, 1.0 / 60.0)
          return game
  </code></pre>
  
  <p>Can someone help me out? Trying to get some random values on the ball. It is from the standard tutorial game on the Kivy framework: Pong Game Tutorial</p>