class Core
{
    private $classes = array();

    public function __get ($class)
    {
        if (!in_array($class, $this->classes))
        {
            if (is_file('classes/'.$class.'.php'))
            {
                require_once 'classes/'.$class.'.php';
                $this->classes[$class] = new $class;
                $this->classes[$class]->Core = $this;
            }
            else
            {
                return false;
            }
        }

        return $this->classes[$class];
    }
}