if (auto_scroll_start)
{
    auto_scroll_start = false;
    with (looping_bg)
        x_speed = -2;
}
if (auto_scroll_stop)
{
    if ((looping_bg.x_pos % 40) == 0)
    {
        auto_scroll_stop = false;
        with (looping_bg)
            x_speed = 0;
    }
}