#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  int h, w;
  cin >> h >> w;
  char s[h + 2][w + 2];
  for (int i = 0; i < w + 2; i++) s[0][i] = '.';
  for (int i = 1; i <= h; i++) {
    s[i][0] = '.';
    for (int j = 1; j <= w; j++) {
      cin >> s[i][j];
    }
    s[i][w + 1] = '.';
  }
  for (int i = 0; i < w + 2; i++) s[h + 1][i] = '.';
  bool ok = false;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (s[i][j] == '.') continue;
      for (int k = -1; k <= 1; k++) {
        for (int l = -1; l <= 1; l++) {
          if (k == 0) continue;
          if (l == 0) continue;
          if (s[i + k][j] == '#') ok = true;
          if (s[i][j + l] == '#') ok = true;
        }
      }
      if (ok == false) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  if (ok) cout << "Yes" << endl;
}
