<?php
abstract class Animal {
public function breath() { return true; }
public function eat() { return true; }
abstract public function makeVoice(); // This means that the function is not defined, but must be in extending classes.
}
class Cat extends Animal {
public function makeVoice() { echo "Meow!"; }
public function destroyFurniture() { return true; } //New function, that is not a part of the parent class.
}