#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int h, w;
  cin >> h >> w;
  string s[h];
  for (int i = 0; i < h; i++) {
    cin >> s[i];
  }
  bool ans = true;
  const int dx[4] = {1, 0, -1, 0};
  const int dy[4] = {0, -1, 0, 1};
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      bool single = true;
      for (int k = 0; k < 4; k++) {
        int tx = i + dx[k], ty = j + dy[k];
        if (tx >= 0 && tx < h && ty >= 0 && ty < w && s[tx][ty] == '#') {
          single = false;
        }
      }
      if (single) {
        ans = false;
      }
    }
  }
  cout << (ans ? "Yes" : "No") << endl;
  return 0;
}
