#include <bits/stdc++.h>
using namespace std;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {-1, 0, 1, 0};
int main() {
  int h, w;
  char t[60][60];
  cin >> h >> w;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> t[i][j];
    }
  }
  bool ans = true;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      if (t[i][j] == '#') {
        bool flag = false;
        for (int k = 0; k < 4; k++) {
          if (t[i + dx[k]][j + dy[k]] == '#') {
            cout << i << j << 'k' << k << endl;
            flag = true;
          }
        }
        if (flag == false) {
          cout << i << j << endl;
          ans = false;
        }
      }
    }
  }
  cout << (ans ? "Yes" : "No") << endl;
}
