#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5;
int w, h, ans, k;
int a[105][105];
int MAX;
int main() {
  cin >> h >> w;
  for (int i = 1; i <= w; i++) {
    for (int j = 1; j <= h; j++) {
      cin >> a[i][j];
    }
  }
  int flag = 0;
  for (int i = 1; i <= w; i++) {
    for (int j = 1; j <= h; j++) {
      if (a[i][j] == '#') {
        if (a[i][j + 1] == '#' || a[i][j - 1] == '#' || a[i + 1][j] == '#' ||
            a[i - 1][j] == '#') {
          flag = 1;
        }
        if (flag == 0) {
          cout << "No" << endl;
          return 0;
        } else {
          flag = 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
}
