index.php

<?php
require_once 'base.php';
ini_set('error_reporting', E_ALL);
ini_set('display_errors', 'on');

$family = array();
$family[] = new Adult('Homer');
$family[] = new Adult('Marge');
$family[] = new Child('Bart');
$family[] = new Child('Lisa');
$boat = new Boat();

$boat->solve($family);
print 'OK!';