PHP Abstraction

Code below defined an TV class. We cannot do much with it except turning it on and off. The class TV is an abstraction of a real TV in a very simple use case.

<?php

class TV {

      private $isOn = false;

      public function turnOn() {

            $this->isOn = true;

               }

     public function turnOff() {

            $this->isOn = false;

               }

}

 $tv = new TV();

$tv->turnOn();

$tv->turnOff();

?>