text: #include <bits/stdc++.h>
  using namespace std;
  
  int main() {
      int h, w;
      cin >> h >> w;
  
      int dx[4] = {0, 1, 0, -1};
      int dy[4] = {1, 0, -1, 0};
  
      char a[h+2][w+2] = {};
      int cnt[h+2][w+2] = {};
      for (int i = 1; i < h+1; i++) {
          for (int j = 1; j < w+1; j++) {
              cin >> a[i][j];
          }
      }
  
      for (int i = 1; i < h+1; i++) {
          for (int j = 1; j < w+1; j++) {
              if (a[i][j] == '#') {
                  for (int k = 0; k < 4; k++) {
                      if (a[i+dx[k]][j+dy[k]] == '#'){
                          cnt[i+dx[k]][j+dy[k]]++;
                      }
                  }
              }
          }
      }
  
      bool test = false;
      for (int i = 1; i < h+1; i++) {
          for (int j = 1; j < w+1; j++) {
              if (a[i][j] == '#' && cnt[i][j] == 0) {
                  test = true;
                  break;
              }
          }
      }
  
      if (test) cout << "No" << endl;
      else cout << "Yes" << endl;
  }