Here is a HUGELY simplified version of my code: from turtle import Turtle, Screen import time speed_x = 20 speed_y = 29 def move_right(): print('exectuted') def game_loop(): ball.goto(ball.xcor() + speed_x, ball.ycor() + speed_y) window.update() window.ontimer(game_loop, 1) window = Screen() time.sleep(2) ball = Turtle(shape='circle') ball.color('white') paddle = Turtle(shape='square') window.onkeypress(move_right, 'Right') window.onkeypress(move_right, 'D') game_loop() window.mainloop() I expected the move_right() function to execute (which for testing should have printed out something) But I get nothing Continue reading...