#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  char s[H][W];
  for (int(i) = 0; (i) < (H); ++(i)) {
    for (int(j) = 0; (j) < (W); ++(j)) {
      cin >> s[j][i];
    }
  }
  bool isAble = true;
  for (int(i) = 0; (i) < (H); ++(i)) {
    for (int(j) = 0; (j) < (W); ++(j)) {
      if (s[i][j] == '#') {
        bool isAbleLocal = false;
        for (int dx = -1; dx <= 1; dx += 2) {
          if (i + dx >= 0 && i + dx <= H - 1) {
            if (s[j][i + dx] == '#') {
              isAbleLocal = true;
            }
          }
        }
        for (int dy = -1; dy <= 1; dy += 2) {
          if (j + dy >= 0 && j + dy <= W - 1) {
            if (s[j + dy][i] == '#') {
              isAbleLocal = true;
            }
          }
        }
        isAble = isAbleLocal;
      }
    }
  }
  string ans = isAble ? "Yes" : "No";
  cout << ans << endl;
}
