import java.util.*; public class Sierpinski { public static List sierpinski(int n) { List down = Arrays.asList("*"); String space = " "; for (int i = 0; i < n; i++) { List newDown = new ArrayList(); for (String x : down) newDown.add(space + x + space); for (String x : down) newDown.add(x + " " + x); down = newDown; space += space; } return down; } public static void main(String[] args) { for (String x : sierpinski(4)) System.out.println(x); } }