#include <bits/stdc++.h>
using namespace std;
using P = pair<long long, long long>;
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 long long MOD = 1e9 + 7;
const long long INF = 1e18;
const double pi = acos(-1);
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int h, w;
  cin >> h >> w;
  vector<string> vec(h);
  for (long long i = 0; i < (h); i++) cin >> vec[i];
  for (long long i = 0; i < (h); i++) {
    for (long long j = 0; j < (w); j++) {
      if (vec[i][j] == '.') continue;
      bool ok = false;
      for (long long k = 0; k < (4); k++) {
        int nx = j + dx[k], ny = i + dx[k];
        if (nx < 0 || w <= nx || ny < 0 || h <= ny) continue;
        if (vec[ny][nx] == '#') ok = true;
      }
      if (!ok) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
}
