PHP OOPS Factory pattern?

[kayessenter]

plz help me understand what am i doing wrong,

<?php

class identity {
function __construct() {
echo __CLASS__;
}
function render() {
echo "<p>Its Working!</p>";
}
}
class User {
function __construct($type) {
if($type=='buyer') {
$user = new Buyer();
}else {
$user = new Seller();
}
return $user;
}
}

class Buyer extends Identity {
}

class Seller extends Identity {
}

$buyer = new User('buyer');

$buyer->render();
?>