#include <bits/stdc++.h>
using namespace std;
using ll = long long;
vector<vector<char>> s(52, vector<char>(52));
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<char>> s(52, vector<char>(52));
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> s.at(i).at(j);
    }
  }
  int count = 0;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      if (s.at(i).at(j) != '#' && s.at(i).at(j - 1) != '#' &&
          s.at(i - 1).at(j) != '#' && s.at(i).at(j + 1) != '#' &&
          s.at(i + 1).at(j) != '#') {
        count++;
      }
    }
  }
  if (count == 0) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
