#include <bits/stdc++.h>
using namespace std;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {-1, 0, 1, 0};
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> A(H, vector<char>(W));
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      cin >> A.at(i).at(j);
    }
  }
  bool b = false;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (A.at(i).at(j) == '.') {
        continue;
      }
      bool a = false;
      for (int d = 0; d < 4; d++) {
        int NX = dx[d] + i;
        int NY = dy[d] + j;
        if (0 <= NX && NX < H && 0 <= NY && NY < W && A.at(NX).at(NY) == '#') {
          a = true;
          break;
        }
      }
      if (!a) {
        b = true;
        break;
      }
    }
    if (b) {
      break;
    }
  }
  if (b) {
    cout << "NO" << endl;
  } else {
    cout << "Yes" << endl;
  }
}
