final int pow = (int) (Math.log(minSize * 2) / Math.log(2));
StringBuilder sb = new StringBuilder("X");
for (int i = 0; i < pow; i++) {
final int pow = (int) (Math.log(minSize * 2) / Math.log(2));
StringBuilder sb = new StringBuilder("X");
for (int i = 0; i < pow; i++) {