#include <iostream>

using namespace std;

static int N=0;
static int M= -1;
static int word_map[50][50] = {0, };
static int max_length = 0;

int FindDiamond(int idx, int jdx, int max_depth){
    //idx, jdx부터 아래로 만들어지는 다이아몬드를 찾으면 최대 길이를, 못찾으면 -1을 반환한다.

    if(word_map[idx][jdx] == 0)
        return -1;

    int depth = 1;
    int mid = 0;
    if(max_depth % 2 == 0)
        mid = max_depth/2;
    else
        mid = max_depth/2 + 1;
    int begin = -1, end = 1;

    int flag = 1;
    while(depth < mid && flag == 1){
        for(int i=(jdx+begin); i<=(jdx+end); i++){
            if(word_map[depth][i] == 0){
                flag = 0;
                break;
            }
        }
        depth++;
        begin--;
        end++;
    }
    if(flag == 0)
        return -1;
    begin++;
    end--;
    while(depth >= mid && begin < end && flag == 1){
        for(int i=(jdx+begin); i<=(jdx+end); i++){
            if(word_map[depth][i] == 0){
                flag = 0;
                break;
            }
        }
        depth++;
        begin++;
        end--;
    }
    return depth;               //depth만큼이 다이아몬드의 최대길이가 되지.
}


int main(void){
    int C=0;
    cin>>C;
    while(C-->0){
        max_length = 0;
        cin>>N;
        getchar();
        int row_cnt=0;
        int word_cnt = 0;
        while(row_cnt < N){
            char ch = getchar();
            if(ch == 10){
                word_cnt = 0;
                row_cnt++;
                continue;
            }
            if(ch == '#')
                word_map[row_cnt][word_cnt] = 1;
            word_cnt++;
            if(word_cnt > M)
                M = word_cnt;
        }

        for(int i=0; i<N; i++){

            for(int j=0; j<M; j++){

                for(int k=N-i; k>0; k--){
                    int length = FindDiamond(i, j, k);
                    if(length > max_length)
                        max_length = length;
                }
            }

        }


        cout<<max_length<<endl;
    }
    return 0;
}