#include <bits/stdc++.h>
using namespace std;
int tab[100][100] = {0};
int h, w;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> h >> w;
  for (int i = 1; i <= (h); i++) {
    string s;
    cin >> s;
    for (int j = 1; j <= (w); j++) {
      if (s.at(j - 1) == '#') tab[i][j] = 1;
    }
  }
  for (int i = 1; i <= (h); i++) {
    int c = 0;
    for (int j = 1; j <= (w); j++) {
      c += tab[i][j + 1];
      c += tab[i][j - 1];
      c += tab[i + 1][j];
      c += tab[i - 1][j];
    }
    if (c == 0) {
      cout << "No\n";
      return 0;
    }
  }
  cout << "Yes\n";
  return 0;
}
