#include <bits/stdc++.h>
using namespace std;
char a[55][55];
int flag;
int main() {
  int n, h, m = 0;
  cin >> n >> h;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= h; j++) {
      cin >> a[i][j];
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= h; j++) {
      m = 1;
      if (a[i][j] == '#') {
        m = 0;
        if (a[i - 1][j] == '#') {
          m++;
          continue;
        }
        if (a[i + 1][j] == '#') {
          m++;
          continue;
        }
        if (a[i][j - 1] == '#') {
          m++;
          continue;
        }
        if (a[i][j + 1] == '#') {
          m++;
          continue;
        }
      }
      if (m == 0) {
        flag = 1;
        cout << i << j << endl;
        break;
      }
    }
  }
  if (flag)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
  return 0;
}
