#include <bits/stdc++.h>
using ll = long long;
enum : int { M = (int)1e9 + 7 };
enum : ll { MLL = (ll)1e18L + 9 };
using namespace std;
template <ostream& out = cout, class... T>
void prints(T&&...) {}
template <ostream& out = cout, class... T>
void printe(T&&...) {}
template <ostream& out = cout, class... T>
void printw(T&&...) {}
template <ostream& out = cout, class... T>
void printew(T&&...) {}
template <ostream& out = cout, class... T>
void printb(T&&...) {}
template <ostream& out = cout, class... T>
void printd(T&&...) {}
template <ostream& out = cout, class... T>
void printde(T&&...){};
template <class S, class T>
istream& operator>>(istream& in, pair<S, T>& p) {
  in >> p.first >> p.second;
  return in;
}
template <class T>
istream& operator>>(istream& in, vector<T>& v) {
  for (auto& e : v) {
    in >> e;
  }
  return in;
}
template <char d = ' ', class T>
ostream& operator<<(ostream& out, vector<T>& v) {
  for (auto& e : v) {
    out << e << d;
  }
  return out;
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int h, w;
  cin >> h >> w;
  vector<string> ss(h);
  cin >> ss;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (ss[i][j] == '.') {
        break;
      }
      if (i + 1 < h && ss[i + 1][j] == '#') {
        break;
      }
      if (j + 1 < w && ss[i][j + 1] == '#') {
        break;
      }
      if (i && ss[i - 1][j] == '#') {
        break;
      }
      if (j && ss[i][j - 1] == '#') {
        break;
      }
      cout << "No" << '\n';
      return 0;
    }
  }
  cout << "Yes" << '\n';
}
