#include <bits/stdc++.h>
using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
void solve() {}
int main() {
  int h, w;
  cin >> h >> w;
  string s[50];
  for (int i = 0; i < h; i++) {
    for (int k = 0; k < w; k++) {
      cin >> s[i][k];
    }
  }
  int dx[4] = {0, 0, 1, -1};
  int dy[4] = {1, -1, 0, 0};
  bool can = true;
  for (int i = 0; i < h; i++) {
    for (int k = 0; k < w; k++) {
      if (s[i][k] == '#') {
        int cnt = 0;
        for (int p = 0; p < 4; p++) {
          int x = k + dx[p];
          int y = i + dy[p];
          if (x >= 0 && x < w && y >= 0 && y < h) {
            if (s[y][x] == '#') {
              cnt++;
            }
          }
        }
        if (cnt == 0) {
          can = false;
        }
      }
    }
  }
  cout << "Yes" << endl;
}
