#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<char>> s(h, vector<char>(w));
  ;
  for (int i = 0; i < (int)(h); i++) {
    ;
    for (int j = 0; j < (int)(w); j++) {
      cin >> s[i][j];
    }
  }
  bool ans = true;
  ;
  for (int i = 0; i < (int)(h); i++) {
    ;
    for (int j = 0; j < (int)(w); j++) {
      bool ok = false;
      if (s[i][j] == '.') continue;
      if (i > 0 && s[i - 1][j] == '#') ok = true;
      if (i < h - 1 && s[i + 1][j] == '#') ok = true;
      if (j > 0 && s[i][j - 1] == '#') ok = true;
      if (j < w - 1 && s[i][j + 1] == '#') ok = true;
      if (ok == false) {
        ans = false;
        cout << i << " " << j << endl;
      }
    }
  }
  if (ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
