Welcome to ZOJ Problem Sets Information Select Problem Runs Ranklist ZOJ Problem Set - 2423
Fractal

Time Limit: 2 Seconds      Memory Limit: 65536 KB

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)
```

Your task is to draw a box fractal of degree n.

Input

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.

Output

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. Don't output any trailing spaces at the end of each line, or you may get an 'Presentation Error'!

Sample Input

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

Sample Output

```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
-
```

Source: Asia 2004, Shanghai (Mainland China), Preliminary
Submit    Status