http://bailian.openjudge.cn/practice/2083

1000ms

65536kB

A fractal is an object or quantity that displays self-similarity, in a somewhat technical sense, on all scales. The object need not exhibit exactly the same structure at all scales, but the same "type" of structures must appear on all scales.
A box fractal is defined as below :
• A box fractal of degree 1 is simply
X
• A box fractal of degree 2 is
X X
X
X X
• If using B(n - 1) to represent the box fractal of degree n - 1, then a box fractal of degree n is defined recursively as following
`B(n - 1)        B(n - 1)        B(n - 1)B(n - 1)        B(n - 1)`

The input consists of several test cases. Each line of the input contains a positive integer n which is no greater than 7. The last line of input is a negative integer −1 indicating the end of input.

For each test case, output the box fractal using the 'X' notation. Please notice that 'X' is an uppercase letter. Print a line with only a single dash after each test case.

```1
2
3
4
-1```

```X
-
X X
X
X X
-
X X   X X
X     X
X X   X X
X X
X
X X
X X   X X
X     X
X X   X X
-
X X   X X         X X   X X
X     X           X     X
X X   X X         X X   X X
X X               X X
X                 X
X X               X X
X X   X X         X X   X X
X     X           X     X
X X   X X         X X   X X
X X   X X
X     X
X X   X X
X X
X
X X
X X   X X
X     X
X X   X X
X X   X X         X X   X X
X     X           X     X
X X   X X         X X   X X
X X               X X
X                 X
X X               X X
X X   X X         X X   X X
X     X           X     X
X X   X X         X X   X X
-```

Shanghai 2004 Preliminary