Tennis is the game where two players or two teams ( one team contains of 2 players) compete with each other. That sport is popular in the whole world. Players (teams) are on opposite sides of the net. One of them is the server and puts the ball into play and serves. The second player is the receiver of the serve. The players' task is to direct the ball with racket strikes towards the opponent's side, while hitting the ball within the boundaries of the court. The player must have time to hit the ball before it touches the court more than once...

Introduction In the last few decades, video games have evolved from crude pixelated diversions into advanced, compelling, and psychologically complex activities that actively shape the manner in which users think, feel, and behave. With 3 billion players worldwide, contemporary game design has transcended entertainment. Designers no longer create merely "fun distractions" — in many ways, they are actually programming human behavior through well-designed systems of reward, challenge, and engagement...