Task
Produce an ASCII representation of a Sierpinski triangle of order   N.



Example
The Sierpinski triangle of order   4   should look like this:

                       *
                      * *
                     *   *
                    * * * *
                   *       *
                  * *     * *
                 *   *   *   *
                * * * * * * * *
               *               *
              * *             * *
             *   *           *   *
            * * * *         * * * *
           *       *       *       *
          * *     * *     * *     * *
         *   *   *   *   *   *   *   *
        * * * * * * * * * * * * * * * *



Related tasks
 Sierpinski triangle/Graphical for graphics images of this pattern. 
 Sierpinski carpet


nOrder=4
call triangle 1, 1, nOrder
end
 
SUB triangle x, y, n
    IF n = 0 THEN
        LOCATE x,y: PRINT "*";
    ELSE
        n=n-1
        length=2^n
        call triangle x, y+length, n
        call triangle x+length, y, n
        call triangle x+length*2, y+length, n
    END IF
END SUB