#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<string> a(h);
  for (int i = 0; i < h; i++) cin >> a[i];
  vector<string> b(h + 2);
  for (int i = 0; i < h + 2; i++) {
    for (int j = 0; j < w + 2; j++) {
      if (i == 0 || i == h + 1 || j == 0 || j == w + 1) {
        b[i][j] = '#';
      } else {
        b[i][j] = a[i - 1][j - 1];
      }
    }
  }
  for (int i = 1; i < h + 1; i++) {
    for (int j = 1; j < w + 1; j++) {
      if (b[i][j] == '#' && (b[i - 1][j] == '.' && b[i][j - 1] == '.' &&
                             b[i + 1][j] == '.' && b[i][j + 1] == '.')) {
        cout << "No";
        return 0;
      }
    }
  }
  cout << "Yes";
  return 0;
}
