pong.kv

<PongBall>:
    size : 50,50
    canvas:
        Ellipse:
            pos : self.pos
            size: self.size

<PongPaddle>:
    size : 25,200
    canvas:
        Rectangle:
            pos : self.pos
            size: self.size

<PongGame>:
    ball : pong_ball
    player1 : player_left
    player2 : player_right
    canvas:
        Rectangle:
            pos : self.center_x - 5, 0
            size: 10, self.height

    Label:
        font_size : 70
        center_x : root.width / 4
        top: root.top - 50
        text:str(root.player2.score)

    Label:
        font_size : 70
        center_x : root.width * 3/4
        top: root.top - 50
        text:str(root.player1.score)

    PongBall:
        id: pong_ball
        center : self.parent.center

    PongPaddle:
        id : player_left
        x : root.x
        center_y : root.center_y

    PongPaddle:
        id : player_right
        x : root.width - self.width
        center_y : root.center_y