A ball bounces along the x-axis between a wall at 0 and another wall at a given distance. The move method advances its position by one unit. When it reaches either wall, it changes direction. What is the behavior of the ball?
1) The ball moves in a straight line towards the wall at a given distance.
2) The ball moves in a straight line towards the wall at 0.
3) The ball moves in a zigzag pattern between the two walls.
4) The ball moves randomly in different directions.