interface iAnimal {
    public function breathe();
    public function die();
    public function birth($method, $gestation);
}

interface iMammal extends iAnimal {
    public function numOfLegs();
    public function colourOfHair();
}

class Dog implements iMammal {

    function __construct($numOfLegs, $colour) {

    }

    public function breathe() {
        //show how to breathe on land and frequency
    }

    public function die() {
        //kill dog
    }

    public function numOfLegs($numOfLegs = 4) {
        //return number of legs
    }

    public function colourOfHair() {
        //return colour of hair
    }

}