题目描述
Problem Statement
For a non-negative integer K, we define a level-K carpet as follows:
- A level-0 carpet is $a 1 \times 1$ grid consisting of a single black cell.
- For K > 0, a level-K carpet is $a 3^K \times 3^K$ grid. When this grid is divided into nine $3^{K-1} \times 3^{K-1}$ blocks:
- The central block consists entirely of white cells.
- The other eight blocks are level-(K-1) carpets.
You are given a non-negative integer N.
Print a level-N carpet according to the specified format.
Input
The input is given from Standard Input in the following format:
N
Output
Print 3^N lines.
The $i-th line (1 \leq i \leq 3^N)$ should contain a string S_i of length 3^N consisting of . and #.
The j-th character of $S_i (1 \leq j \leq 3^N)$ should be # if the cell at the i-th row from the top and j-th column from the left of a level-N carpet is black, and . if it is white.
Constraints
- $0 \leq N \leq 6$
- N is an integer.
Sample Input 1
1
Sample Output 1
.
A level-1 carpet is $a 3 \times 3$ grid as follows:
When output according to the specified format, it looks like the sample output.
Sample Input 2
2
Sample Output 2
.##.##.
...
.#...#.
...
.##.##.
A level-2 carpet is $a 9 \times 9$ grid.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分