#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<string> vec;
  for (int i = 0; i < (int)(h); i++) {
    string str;
    cin >> str;
    vec.push_back(str);
  }
  for (int i = 0; i < (int)(h); i++) {
    for (int j = 0; j < (int)(w); j++) {
      if (vec[i][j] == '.')
        continue;
      else {
        bool found = false;
        for (int x = -1, y = 0, k = 0; k < 4;
             x += y, y = x - y, x = y - x, ++k) {
          if ((0 <= i + y) && (i + y < h) && (0 <= j + x) && (j + x < w)) {
            if (vec[i + y][j + x] == '#') {
              cout << i << " " << j << endl;
              found = true;
            }
          }
        }
        if (!found) {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
