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