#include <bits/stdc++.h>
using namespace std;
void Main() {
  int H, W;
  cin >> H >> W;
  vector<string> S(H);
  for (int i = 0; i < H; i++) cin >> S[i];
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (S[i][j] == '.') continue;
      bool ok = false;
      if (i > 0)
        if (S[i - 1][j] == '#') ok = true;
      if (i < H - 1)
        if (S[i + 1][j] == '#') ok = true;
      if (j > 0)
        if (S[i][j - 1] == '#') ok = true;
      if (j < W - 1)
        if (S[i][j + 1] == '#') ok = true;
      if (!ok) {
        cout << "NO" << endl;
        ;
        return;
      }
    }
  }
  cout << "YES" << endl;
  ;
}
int main() {
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  Main();
}
