#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
const int INF = 1e9;
int H, W;
string s[55] = {"."};
int main() {
  cin >> H >> W;
  for (int i = 0; i < (H); ++i) cin >> s[i];
  for (int i = 0; i < (H); ++i) {
    for (int j = 0; j < (W); ++j) {
      if (s[i][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;
}
