#include <bits/stdc++.h>
using namespace std;
template <typename A, typename B, typename C>
struct triple {
  A X;
  B Y;
  C Z;
  triple(A a = 0, B b = 0, C c = 0) : X(a), Y(b), Z(c) {}
};
template <typename A, typename B, typename C>
triple<A, B, C> make_triple(A a = 0, B b = 0, C c = 0) {
  return triple<A, B, C>(a, b, c);
}
template <typename A, typename B, typename C>
bool operator<(const triple<A, B, C>& a, const triple<A, B, C>& b) {
  if (a.X != b.X) return a.X < b.X;
  if (a.Y != b.Y) return a.Y < b.Y;
  return a.Z < b.Z;
}
template <typename T, typename SS>
ostream& operator<<(ostream& ofs, const pair<T, SS>& p) {
  ofs << "( " << p.first << " , " << p.second << " )";
  return ofs;
}
template <typename T>
void print(T a, long long z) {
  for (auto i : a) cout << i + z << ' ';
  cout << '\n';
}
template <typename T>
T max(T a, T b, T c) {
  return max(a, max(b, c));
}
template <typename T>
T min(T a, T b, T c) {
  return min(a, min(b, c));
}
template <typename T, typename D>
D min(T a) {
  return *min_element(a.begin(), a.end());
}
template <typename T, typename D>
D max(T a) {
  return *max_element(a.begin(), a.end());
}
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
vector<vector<long long> > rr;
bool rec(vector<vector<long long> > s, long long c) {
  if (s[0][0] + s[0][1] + s[1][0] + s[1][1] == 0) return 1;
  if (c == 4) return 0;
  for (long long i = 0; i < (2); i++)
    for (long long j = 0; j < (2); j++) {
      rr.push_back(vector<long long>());
      for (long long t = 0; t < (2); t++)
        for (long long v = 0; v < (2); v++)
          if (t != i || v != j) {
            s[t][v] ^= 1;
            rr.back().push_back(t);
            rr.back().push_back(v);
          }
      if (rec(s, c + 1)) return 1;
      for (long long t = 0; t < (2); t++)
        for (long long v = 0; v < (2); v++)
          if (t != i || v != j) {
            s[t][v] ^= 1;
            rr.back().pop_back();
            rr.back().pop_back();
          }
      rr.pop_back();
    }
  return 0;
}
void solve() {
  long long n, m;
  cin >> n >> m;
  vector<string> s(n);
  for (long long i = 0; i < (n); i++) cin >> s[i];
  for (long long i = 0; i < (n); i++)
    for (long long j = 0; j < (m); j++) s[i][j] -= '0';
  vector<vector<long long> > ans;
  for (long long j = 0; j < m - 2; j++)
    for (long long i = 0; i < (n); i++)
      if (s[i][j]) {
        if (i + 1 < n) {
          ans.push_back(vector<long long>({i, j, i, j + 1, i + 1, j + 1}));
          s[i][j] ^= 1;
          s[i][j + 1] ^= 1;
          s[i + 1][j + 1] ^= 1;
        } else {
          ans.push_back(vector<long long>({i, j, i, j + 1, i - 1, j + 1}));
          s[i][j] ^= 1;
          s[i][j + 1] ^= 1;
          s[i - 1][j + 1] ^= 1;
        }
      }
  for (long long i = 0; i < (n - 2); i++) {
    string t = string(1, '0' + s[i][m - 2]) + string(1, '0' + s[i][m - 1]);
    if (t == "00") continue;
    if (t == "11") {
      ans.push_back({i, m - 2, i, m - 1, i + 1, m - 1});
      s[i][m - 2] ^= 1;
      s[i][m - 1] ^= 1;
      s[i + 1][m - 1] ^= 1;
    }
    if (t == "01") {
      ans.push_back({i, m - 1, i + 1, m - 1, i + 1, m - 2});
      s[i][m - 1] ^= 1;
      s[i + 1][m - 1] ^= 1;
      s[i + 1][m - 2] ^= 1;
    }
    if (t == "10") {
      ans.push_back({i, m - 2, i + 1, m - 1, i + 1, m - 2});
      s[i][m - 2] ^= 1;
      s[i + 1][m - 1] ^= 1;
      s[i + 1][m - 2] ^= 1;
    }
  }
  vector<vector<long long> > sq(2, vector<long long>(2));
  rr.clear();
  sq[0][0] = s[n - 2][m - 2];
  sq[0][1] = s[n - 2][m - 1];
  sq[1][0] = s[n - 1][m - 2];
  sq[1][1] = s[n - 1][m - 1];
  auto z = rec(sq, 0);
  for (auto v : rr) {
    ans.push_back(v);
    ans.back()[0] += n - 2;
    ans.back()[2] += n - 2;
    ans.back()[4] += n - 2;
    ans.back()[1] += m - 2;
    ans.back()[3] += m - 2;
    ans.back()[5] += m - 2;
  }
  cout << (long long)(ans.size()) << '\n';
  for (auto v : ans) {
    print(v, 1);
  }
};
signed main() {
  if (0) {
    freopen(
        "a"
        ".in",
        "r", stdin);
    freopen(
        "a"
        ".out",
        "w", stdout);
  }
  srand(time(NULL));
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(false);
  long long t = 1;
  cin >> t;
  for (long long _ = 0; _ < (t); _++) solve();
}
