#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[i][j];
  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++) {
      if (s[i][j] == '.') continue;
      bool ok = false;
      for (int y = -1; y <= 1; y += 2) {
        int dy = i + y;
        if (dy > 0 && dy < h && s[dy][j] == '#') ok = true;
      }
      for (int x = -1; x <= 1; x += 2) {
        int dx = j + x;
        if (dx > 0 && dx < w && s[i][dx] == '#') ok = true;
      }
      if (!ok) {
        cout << "No" << endl;
        return 0;
      }
    }
  cout << "Yes" << endl;
  return 0;
}
