Control the horizontal line moves up by left or right. When the line is tilted, the little red ball rolls because
of downward gravity. By controlling the horizontal line, push the ball toward the blue hole. The red ball just moves
into the blue hole, and at low enough speed, it enters the hole and goes to the next level.
The balls and holes get smaller and smaller, and the balls move more and more sensitively.
The line can only go forward, not backward, and you have to take every chance.