/*

* if Penguin re-defines (overrides)

* the parent Bird constructor,

* you may need to explictly invoke it

* in order to pass along the parameter values

*

* if Penguin does not re-define the constructor,

* this is not required

* */

public function __construct($eyeColor, $song){

/*

* explicitly call the parent constructor to ensure it is run

* */

parent::__construct($eyeColor, $song);

echo "<p>A Penguin is born!</p>";

}

/*

* add to the parent's functions

* */

public function swim(){

echo "<p>Swim swim...</p>";

}

/*

* override the parents functions...

* */

public function fly(){

echo "<p>Penguins don't fly. Good luck trying...</p>";

}