#include <bits/stdc++.h>
using namespace std;
int main(void) {
  bool tf = true;
  int h, w;
  cin >> h >> w;
  string s[100];
  for (int i = 0; i < h; i++) {
    cin >> s[i];
  }
  const int dx[4] = {1, 0, -1, 0};
  const int dy[4] = {0, -1, 0, 1};
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (s[i][j] == '.') {
        continue;
      }
      bool tf2 = false;
      for (int k = 0; k < 4; k++) {
        int n1 = i + dx[k];
        int n2 = i + dy[k];
        if (n1 < 0 || h <= n1) {
          continue;
        }
        if (n2 < 0 || w <= n2) {
          continue;
        }
        if (s[n1][n2] == '#') {
          tf2 = true;
        }
      }
      if (tf2 == false) {
        tf = false;
        goto finish;
      }
    }
  }
  if (tf == true) {
    cout << "Yes" << endl;
  }
finish:
  if (tf = false) {
    cout << "No" << endl;
  }
  return 0;
}
