#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
const ll INF = 1000000000000000;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<int>> a(h + 2, vector<int>(w + 2));
  char t53;
  for (int i = 1; i < (h + 1); i++) {
    for (int j = 1; j < (h + 1); j++) {
      cin >> t53;
      if (t53 == '.')
        a.at(i).at(j) = 0;
      else
        a.at(i).at(j) = 1;
    }
  }
  int count;
  for (int i = 1; i < (h + 1); i++) {
    for (int j = 1; j < (w + 1); j++) {
      count = 0;
      if (a.at(i).at(j) == 1) {
        count += a.at(i - 1).at(j);
        count += a.at(i).at(j - 1);
        count += a.at(i).at(j + 1);
        count += a.at(i + 1).at(j);
        if (count == 0) {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
}
