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


const size = 1 shl 4 - 1
 
for y in countdown(size, 0):
  for i in 0 .. <y:
    stdout.write " "
  for x in 0 .. size-y:
    if (x and y) != 0:
      stdout.write "  "
    else:
      stdout.write "* "
  stdout.write "\n"