#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool amax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool amin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
int GCD(int a, int b) { return b ? GCD(b, a % b) : a; }
long long GCD(long long a, long long b) { return b ? GCD(b, a % b) : a; }
int LCM(int a, int b) { return a * b / GCD(a, b); }
long long LCM(long long a, long long b) { return a * b / GCD(a, b); }
struct aaa {
  aaa() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} aaaaaaa;
const int INF = 1001001001;
const long long LINF = 1001001001001001001ll;
const int MOD = 1e9 + 7;
const double EPS = 1e-9;
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
signed main() {
  int h, w;
  cin >> h >> w;
  vector<string> v(h);
  for (int i = 0, i_len = (int)h; i < i_len; ++i) {
    cin >> v.at(i);
  }
  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      int cnt{};
      for (int k = 0; k < 4; ++k) {
        int x{}, y{};
        x = i + dx[k];
        y = j + dy[k];
        if (v[x][y] != '#') {
          cnt++;
        }
      }
      cnt -= 4;
      if (cnt == 0) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
