#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
char s[55][55];
int main() {
  int h, w;
  cin >> h >> w;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> s[i][j];
    }
  }
  int cnt = 0;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      if (s[i - 1][j] != '#' && s[i + 1][j] != '#' && s[i][j - 1] != '#' &&
          s[i][j + 1] != '#')
        cnt++;
    }
  }
  if (cnt == 0)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
