public function writePoint(QtiPoint $point)
    {
       try {
           $this->writeShort($point->getX());
           $this->writeShort($point->getY());
       } catch (BinaryStreamAccessException $e) {
           $msg = "An error occured while writing a point.";
           throw new QtiBinaryStreamAccessException($msg, $this, QtiBinaryStreamAccessException::POINT, $e);
       }
    }