/**
*  Problem Name: Plus_of_Pluses
*  Author: MJS
*  Created: 16 December 2024, Monday (14:12:01)...
**/

#include<bits/stdc++.h>
using namespace std;

#define ll long long int
#define nl '\n' 

struct g{
    int l,r,u,d;
};

int n,m;
char c[2002][2002];
g dp[2002][2002];

void answer_to_the_question(){
    cin>>n>>m;
    for(int i=0;i<=n+1;i++){
        for(int j=0;j<=m+1;j++){
            dp[i][j].l=dp[i][j].r=dp[i][j].u=dp[i][j].d=-1;
            c[i][j]='-';
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>c[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(c[i][j]=='+'){
                dp[i][j].l=dp[i][j-1].l+1;
            }
        }
        for(int j=m;j>0;j--){
            if(c[i][j]=='+'){
                dp[i][j].r=dp[i][j+1].r+1;
            }
        }
    }
    for(int i=1;i<=m;i++){
        for(int j=1;j<=n;j++){
            if(c[j][i]=='+'){
                dp[j][i].u=dp[j-1][i].u+1;
            }
        }
        for(int j=n;j>0;j--){
            if(c[j][i]=='+'){
                dp[j][i].d=dp[j+1][i].d+1;
            }
        }
    }
    int ans=0;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            int mn=min({dp[i][j].l,dp[i][j].r,dp[i][j].u,dp[i][j].d});
            ans=max(ans,4*mn+1);
        }
    }
    cout<<ans<<nl;
}

int32_t main(){
    ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    int test_case;    cin>>test_case;

    for(int MJS=1; MJS<=test_case; MJS++){
        answer_to_the_question();
    }

    return 0;
}

// Hi..