I am creating the Pong game using the Turtle module in Python. So far, I have one file for the paddles (the bars that players control to hit the ball) called paddles.py and a second file for the main gameplay control called game.py. I still plan on making a file for the ball and another for score-keeping.

In my paddles file, I create a Paddle class using the Turtle class. It doesn’t exactly inherit from Turtle, but instead creates several Turtle instances inside each Paddle. I made a condition inside the __init__ of Paddle which sets a “left” paddle to the left and a “right” paddle to the right. Then I import the Paddle file to game.py and create a left_pad and a right_pad as follows:

left_pad = Paddle("left")
right_pad = Paddle("right")

On running the game.py file, the left_pad appears briefly then disappears, then only the right_pad is actually showing on the screen.

The shape is correct, the positioning is correct, but the left_pad is simply not there.

Here is the code for paddles.py (for now I am not worried about the moving functions):

from turtle import Turtle

class Paddle:
    side = ""
    paddle = [Turtle(shape="square") for i in range(4)]
    paddle_bottom = -30
    paddle_range = []


    def __init__(self, side):
        self.side = side
        self.paddle_range = [self.paddle[0].screen.canvheight-10, -self.paddle[0].screen.canvheight+10]

        for box in range(len(self.paddle)):
            self.paddle[box].penup()

        # Set to middle height
        for box in range(len(self.paddle)):
            self.paddle[box].sety(self.paddle_bottom + 20*box)
        
        # Set to sides
        if side == "left":
            for box in range(len(self.paddle)):
                self.paddle[box].setx((-self.paddle[0].screen.canvwidth / 2) + 20)
        else:
            for box in range(len(self.paddle)):
                self.paddle[box].setx((self.paddle[0].screen.canvwidth / 2) - 20)


    def move():
        global paddle
        for box in len(range(paddle)):
            paddle[box].forward(1)
        paddle[0].screen.update()


    def move_up():
        global paddle_range
        global move
        for box in len(range(paddle)):
            paddle[box].setheading(90)
        while paddle[-1].ycor() < paddle_range[0]:
            move()


    def move_down():
        for box in len(range(paddle)):
            paddle[box].setheading(270)
        while paddle[0].ycor() > paddle_range[1]:
            move()


    if side == "left":
        paddle[0].screen.onkey(key="w", fun=move_up)
        paddle[0].screen.onkey(key="s", fun=move_down)
    else:
        paddle[0].screen.onkey(key="Up", fun=move_up)
        paddle[0].screen.onkey(key="Down", fun=move_down)

and the game.py:

from turtle import Screen
from paddles import Paddle

screen = Screen()
screen.bgcolor("beige")
screen.title("Pong!")
screen.setup(width=820, height=620)
screen.screensize(canvwidth=800, canvheight=600)
screen.tracer(0)
screen.listen()


left_pad = Paddle("left")
screen.update()
right_pad = Paddle("right")
screen.update()


screen.exitonclick()