#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  bool s[52][52] = {};
  cin >> h >> w;
  for (int i = 1; i <= h; i++) {
    string str;
    cin >> str;
    for (int j = 1; j <= w; j++) {
      if (str[j - 1] == '#') {
        s[i][j] = true;
      } else {
        s[i][j] = false;
      }
    }
  }
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      if (s[i][j]) {
        if (!(s[i - 1][j] || s[i + 1][j] || s[i][j - 1] || s[i][j + 1])) {
          return 0;
        }
      }
    }
  }
  cout << "YES" << endl;
  return 0;
}
