#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<string> S;
  S.resize(h);
  for (int i = 0; i < h; i++) {
    S[i].resize(w);
    for (int j = 0; j < w; j++) {
      cin >> S[i][j];
    }
  }
  int flag = 0;
  for (int i = 1; i < h - 1; i++) {
    for (int j = 1; j < w - 1; j++) {
      if (S[i][j] == '#') {
        flag = 0;
        if (S[i - 1][j] == S[i][j]) {
          flag = 1;
          break;
        }
        if (S[i][j - 1] == S[i][j]) {
          flag = 1;
          break;
        }
        if (S[i][j + 1] == S[i][j]) {
          flag = 1;
          break;
        }
        if (S[i + 1][j] == S[i][j]) {
          flag = 1;
          break;
        }
      } else {
        flag = 1;
      }
    }
    if (flag == 0) break;
  }
  if (flag >= 1)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  system("pause");
  return 0;
}
