#include <bits/stdc++.h>
using namespace std;
using ll = 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 int INF = 1001001001;
const long long INFLL = LLONG_MAX / 3;
const double eps = (1e-9);
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  for (ll i = 0; i < h; ++i) cin >> s[i];
  for (ll i = 0; i < h; ++i)
    for (ll j = 0; j < w; ++j) {
      if (s[i][j] == '.') continue;
      if (i > 0 && s[i - 1][j] == '#') continue;
      if (i < h - 2 && s[i + 1][j] == '#') continue;
      if (j > 0 && s[i][j - 1] == '#') continue;
      if (j < w - 2 && s[i][j + 1] == '#') continue;
      puts("No");
      return 0;
    }
  puts("Yes");
  return 0;
}
