Bouncing Off the Wall

The term Back and Forth applies to many situations in life. Our daily travel to work goes in that particular rhythm. So does the flow of conversation between 2 persons, I said something and you say something...and so it goes.
But the back and forth action can be applied in a attack and defend mechanism. Particularly in games....attack when you are strong...defend when you need a break. But in this case the opponent is a stiff wall. The tennis ball just goes back and forth because somebody needs to practise his shots...real badly.