#include <bits/stdc++.h>
using namespace std;
inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T>
inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
const double EPS = 1e-10;
const double PI = acos(-1.0);
const int INF = (int)1000000007;
const long long MOD = (long long)1000000007;
const long long INF2 = (long long)100000000000000000;
char tb[55][55];
int main() {
  int h, w;
  cin >> h >> w;
  for (int i = 0; i < h; i++) {
    string buf;
    cin >> buf;
    for (int j = 0; j < buf.size(); j++) {
      tb[i + 1][j + 1] = buf[j];
    }
  }
  int dy[4] = {0, 1, 0, -1};
  int dx[4] = {1, 0, -1, 0};
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      bool ok = false;
      if (tb[i + 1][j + 1] == '#') {
        for (int d = 0; d < 4; d++) {
          if (tb[i + 1 + dy[d]][j + 1 + dx[d]] == '#') {
            ok = true;
          }
        }
      }
      if (!ok) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
