#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<char>> data(h, vector<char>(w));
  vector<int> dx = {-1, 0, 1, 0};
  vector<int> dy = {0, 1, 0, -1};
  bool judge = true;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (data.at(i).at(j) == '#') {
        int cnt = 0;
        for (int k = 0; k < 4; k++) {
          int x = i + dx.at(k);
          int y = j + dy.at(k);
          if (x >= 0 && x < h && y >= 0 && y < w && data.at(x).at(y) == '#') {
            cnt++;
          }
        }
        if (cnt == 0) {
          judge = false;
        }
      }
    }
  }
  if (judge) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
