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

typedef int64_t ll;

#ifdef LOCAL
#include "debug.hpp"
#else
#define debug(...) 42
#endif

const ll N = 2009;
ll a[N][N], pref[N][N];

ll query(ll y1, ll y2, ll x1, ll x2) {
    return pref[x2][y2] - pref[x1 - 1][y2] - pref[x2][y1 - 1] + pref[x1 - 1][y1 - 1];
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll T;
    cin >> T;
    while (T--) {
        ll n, m;
        cin >> n >> m;
        for (ll i = 1; i <= n; i++) {
            for (ll j = 1; j <= m; j++) {
                char c;
                cin >> c;
                if (c == '+') {
                    a[i][j] = 1;
                } else {
                    a[i][j] = 0;
                }
            }
        }
        for (ll i = 1; i <= n; i++) {
            for (ll j = 1; j <= m; j++) {
                pref[i][j] = pref[i - 1][j] + pref[i][j - 1] - pref[i - 1][j - 1] + a[i][j];
            }
        }
        ll res = 0;
        for (ll i = 1; i <= n; i++) {
            for (ll j = 1; j <= m; j++) {
                if (a[i][j] == 0)
                    continue;
                ll l = 0, r = min(j - 1, m - j), ret = 0;
                while (l <= r) {
                    ll m = l + r >> 1;
                    if (m == 0 || (query(j - m, j - 1, i, i) == m && query(j + 1, j + m, i, i) == m)) {
                        ret = m;
                        l = m + 1;
                    } else {
                        r = m - 1;
                    }
                }
                l = 0, r = min({ret, i - 1, n - i});
                while (l <= r) {
                    ll m = l + r >> 1;
                    if (m == 0 || (query(j, j, i - m, i - 1) == m && query(j, j, i + 1, i + m) == m)) {
                        ret = m;
                        l = m + 1;
                    } else {
                        r = m - 1;
                    }
                }
                res = max(res, ret * 4 + 1);
            }
        }
        cout << res << '\n';
    }
}