#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> D(H, vector<char>(W));
  for (int X = 0; X < H; X++) {
    for (int Y = 0; Y < W; Y++) {
      cin >> D[X][Y];
    }
  }
  bool J = true;
  for (int X = 0; X < H; X++) {
    for (int Y = 0; Y < W; Y++) {
      if (D[X][Y] == '#' && D[X + 1][Y] == '.' && D[X - 1][Y] == '.' &&
          D[X][Y + 1] == '.' && D[X][Y - 1] == '.') {
        J = false;
      }
    }
  }
  if (J) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
