#include <bits/stdc++.h>
using namespace std;
int main() {
  int X, Y;
  bool can = true;
  cin >> X >> Y;
  string board[60];
  for (int(i) = 0; i < (X); ++i) cin >> board[i];
  for (int(i) = 0; i < (X); ++i) {
    for (int(j) = 0; j < (Y); ++j) {
      int cnt = 0;
      if (board[i][j] == '#') {
        if (board[i - 1][j] == '.' && board[i + 1][j] == '.' &&
            board[i][j + 1] == '.' && board[i][j - 1] == '.')
          cnt++;
        if (cnt) {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
