You were playing ping pong with your friend. Suddenly the ball fell into a narrow metal pipe that was imbedded in the concrete surface of the floor one foot deep. Now you dont have any other ball and you desperately want to take it out and play. You and your friend have your shoe laces, your tennis paddle and a plastic water bottle. However the bottle cannot fit into the pipe.
How will you take the ball out?
All the tools you have are just given to draw your attention. In reality, you wont be using any one of them to take out that ball. It is a ping pong ball right? You have a water bottle too. Just empty the bottle in that narrow hole and your ball will float to the top automatically.