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


function sierpinski(n : Integer) {
  var down = ["*"];
  var space = " ";
  for (i in [1..n]) {
    down = [for (x in down) "{space}{x}{space}", for (x in down) "{x} {x}"];
    space = "{space}{space}";
  }
 
  for (x in down) {
    println("{x}")
  }
}
 
sierpinski(4);