public static function asciiBorder()
    {
        if (!self::$asciiBorder) {
            self::$asciiBorder = new static();
            self::$asciiBorder->headerCellFormat = ' %s ';
            self::$asciiBorder->cellFormat = ' %s ';
            self::$asciiBorder->borderStyle = BorderStyle::ascii();
        }

        return clone self::$asciiBorder;
    }