#include <bits/stdc++.h>
using ll = long long;
using namespace std;
int di[4] = {-1, 0, 0, 1};
int dj[4] = {0, -1, 0, 1};
int main() {
  int h, w;
  cin >> h >> w;
  string s[h];
  for (int i = 0; i < (h); i++) {
    cin >> s[i];
  }
  bool ans = true;
  for (int i = 0; i < (h); i++) {
    for (int j = 0; j < (w); j++) {
      if (s[i][j] != '#') {
        continue;
      }
      bool ok = false;
      for (int k = 0; k < 5; k++) {
        int ni = i + di[k];
        int nj = j + dj[k];
        if (ni < 0 || ni >= h || nj < 0 || nj >= w) continue;
        if (s[ni][nj] == '#') ok = true;
      }
      if (!ok) {
        ans = false;
        break;
      }
    }
  }
  if (ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
