#include <bits/stdc++.h>
using namespace std;
const long long INF = 1LL << 60;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<int>> v(50, vector<int>(50));
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      cin >> v[i][j];
    }
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (v[i][j] == '#' && v[i][j + 1] == '.' && v[i][j - 1] == '.' &&
          v[i + 1][j] == '.' && v[i - 1][j] == '.') {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
}
