#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC optimize(3)
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC target("sse3", "sse2", "sse")
#pragma GCC target("avx", "sse4", "sse4.1", "sse4.2", "ssse3")
#pragma GCC target("f16c")
#pragma GCC optimize("inline", "fast-math", "unroll-loops", \
                     "no-stack-protector")
#pragma GCC push_options
#pragma GCC pop_options
#pragma GCC reset_options
#pragma GCC optimize("O3")
const double eps = 1e-9;
const int INFMEM = 63;
const int INF = 1061109567;
const long long LINF = 4557430888798830399LL;
const double DINF = numeric_limits<double>::infinity();
const long long MOD = 1000000007;
const int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
const int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};
const double PI = 3.141592653589793;
inline void fastll(long long &input_number) {
  input_number = 0;
  int ch = getchar_unlocked();
  int sign = 1;
  while (ch < '0' || ch > '9') {
    if (ch == '-') sign = -1;
    ch = getchar_unlocked();
  }
  while (ch >= '0' && ch <= '9') {
    input_number = (input_number << 3) + (input_number << 1) + ch - '0';
    ch = getchar_unlocked();
  }
  input_number *= sign;
}
inline void open(string a) {
  freopen((a + ".in").c_str(), "r", stdin);
  freopen((a + ".out").c_str(), "w", stdout);
}
inline void fasterios() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
long long t;
struct dt {
  long long x, y;
};
char ori[2005][2005];
char ans[2005][2005];
vector<dt> pos[27];
dt st[27], ed[27];
int main() {
  cin >> t;
  while (t--) {
    long long r, c;
    cin >> r >> c;
    for (int i = 0; i < 26; i++) {
      pos[i].clear();
      st[i] = ed[i] = {-1, -1};
    }
    for (int i = 1; i <= r; i++) {
      for (int j = 1; j <= c; j++) {
        cin >> ori[i][j];
        ans[i][j] = '.';
        if (ori[i][j] == '.') continue;
        pos[ori[i][j] - 'a'].push_back({i, j});
      }
    }
    bool validDirection = 1;
    for (int i = 0; i < 26; i++) {
      if (pos[i].size() == 0) continue;
      st[i].x = st[i].y = LINF;
      ed[i].x = ed[i].y = -LINF;
      for (int j = 0; j < pos[i].size(); j++) {
        st[i].x = min(st[i].x, pos[i][j].x);
        ed[i].x = max(ed[i].x, pos[i][j].x);
        st[i].y = min(st[i].y, pos[i][j].y);
        ed[i].y = max(ed[i].y, pos[i][j].y);
      }
      if (st[i].x != ed[i].x && st[i].y != ed[i].y) {
        validDirection = 0;
        break;
      }
    }
    if (!validDirection) {
      cout << "NO" << '\n';
      continue;
    }
    for (int l = 0; l < 26; l++) {
      if (pos[l].size() == 0) continue;
      for (int i = st[l].x; i <= ed[l].x; i++) {
        for (int j = st[l].y; j <= ed[l].y; j++) {
          ans[i][j] = (char)(l + 'a');
        }
      }
    }
    bool flag = 1;
    for (int i = 1; i <= r; i++) {
      for (int j = 1; j <= c; j++) {
        if (ori[i][j] != ans[i][j]) {
          flag = 0;
          break;
        }
      }
      if (!flag) break;
    }
    if (!flag) {
      cout << "NO" << '\n';
      continue;
    }
    cout << "YES" << '\n';
    long long maksIdx = -1;
    for (int i = 25; i >= 0; i--) {
      if (pos[i].size() > 0) {
        maksIdx = i;
        break;
      }
    }
    if (maksIdx == -1) {
      cout << 0 << '\n';
      continue;
    }
    cout << maksIdx + 1 << '\n';
    for (int i = 0; i < 26; i++) {
      long long now = i;
      if (st[i].x == -1) now = maksIdx;
      cout << st[now].x << " " << st[now].y << " " << ed[now].x << " "
           << ed[now].y << '\n';
      if (i == maksIdx) break;
    }
  }
  return 0;
}
