Romb

    public static void main(String[] args) {
        int n = 8, r;

        for (int i=0; i<2*n+1; i++) {
            for (int j=0; j<2*n+1; j++){

                if (i>n)
                    r = 2*n - i;
                else
                    r = i;

                if ((j>n-r-1) && (j<n+r+1))
                    System.out.print('X');
                else
                    System.out.print('-');
            }
            System.out.println();
        }

    }