#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<int>> field(h + 2, vector<int>(w + 2, 0));
  for (int y = 0; y < (h); ++y) {
    string s;
    cin >> s;
    for (int x = 0; x < (w); ++x) {
      if (s[x] == '#') field[y + 1][x + 1] = 1;
    }
  }
  for (int y = 0; y < (h); ++y) {
    for (int x = 0; x < (w); ++x) {
      int cx = x + 1;
      int cy = y + 1;
      bool is_able = false;
      if (field[cy][cx - 1]) is_able = true;
      if (field[cy][cx + 1]) is_able = true;
      if (field[cy - 1][cx]) is_able = true;
      if (field[cy + 1][cx]) is_able = true;
      if (!is_able) {
        cout << "No";
        return 0;
      }
    }
  }
  cout << "Yes";
  return 0;
}
