#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  char s[h + 2][w + 2];
  for (int i = 1; i < h + 1; i++) {
    for (int j = 1; j < w + 1; j++) {
      cin >> s[i][j];
    }
  }
  for (int i = 1; i < h + 1; i++) {
    for (int j = 1; j < w + 1; j++) {
      bool is = false;
      if (s[i][j] == '.') {
        continue;
      }
      if (s[i][j - 1] == '#' || s[i][j + 1] == '#' || s[i + 1][j] == '#' ||
          s[i - 1][j] == '#') {
        is = true;
      }
      if (is == false) {
        cout << "No";
      }
    }
  }
  cout << "Yes";
}
