#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> map(H, vector<char>(W));
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      cin >> map.at(i).at(j);
    }
  }
  bool OK = true;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      bool independent = true;
      if (i + 1 < H) {
        if (map.at(i + 1).at(j) == '#') independent = false;
      }
      if (i - 1 >= 0) {
        if (map.at(i - 1).at(j) == '#') independent = false;
      }
      if (j + 1 < W) {
        if (map.at(i).at(j + 1) == '#') independent = false;
      }
      if (j - 1 >= 0) {
        if (map.at(i).at(j - 1) == '#') independent = false;
      }
      if (independent) OK = false;
    }
  }
  if (OK)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
