#include <bits/stdc++.h>
using namespace std;
const unsigned long long BIGEST = 1000000000000000000 + 1000000000000000000;
const long long BIGER = 1000000000000000000;
const int BIG = 1000000000;
const int MOD = 19260817;
char c[1001][1001] = {'*'};
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    scanf("\n");
    for (int j = 1; j <= m; j++) {
      scanf("%c", &c[i][j]);
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (c[i][j] = '#' && c[i - 1][j] == '.' && c[i + 1][j] == '.' &&
                    c[i][j - 1] == '.' && c[i][j + 1] == '.') {
        cout << "No";
        return 0;
      }
    }
  }
  cout << "Yes";
  return 0;
  return 0;
}
