def update_world():
    "Crash, move, and mutate the balls."
    global world_h, world
    for index, ball_1 in enumerate(balls[:-1]):
        for ball_2 in balls[index+1:]:
            ball_1.crash(ball_2)
    for ball in balls:
        ball.err *= PHY.B_BONUS
        ball.correct()
        governor(ball)
        ball.move(TMR.P_FPS)
        for mutate in wall, floor, gravity, friction:
            mutate(ball)
    world += 1
    world_h = screen.after(int((start + world / TMR.P_FPS - time.clock()) * 1000), update_world)
Crash, move, and mutate the balls.
recipes/Python/510398_Kaos_Rain_MKv3/recipe-510398.py