public function svg()
    {
        if (count($this->arr_points) < 3) {
            throw new \RuntimeException('Before exporting to SVG, you must give at least 3 points!');
        }

        $arr = array();

        foreach ($this->arr_points as $point) {
            $arr[] = implode(',', $point);
        }

        $str_attr_points = implode(' ', $arr);

        return sprintf('<polygon points="%s" style="fill:%s" />', $str_attr_points, $this->color);
    }