#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 29;
const double EPS = 1e-9;
const int dx[] = {1, 0, -1, 0, 1, 1, -1, -1},
          dy[] = {0, -1, 0, 1, 1, -1, -1, 1};
int main() {
  int H, W;
  cin >> H >> W;
  vector<string> M(H);
  for (int i = 0; i < H; i++) {
    cin >> M[i];
  }
  bool ans = true;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < H; j++) {
      bool ok = false;
      if (M[i][j] == '.') continue;
      for (int k = 0; k < 4; k++) {
        int tx = j + dx[k];
        int ty = i + dy[k];
        if (tx < 0 || tx >= W || ty < 0 || ty >= H) continue;
        if (M[ty][tx] == '#') {
          ok = true;
        }
      }
      if (!ok) {
        ans = false;
      }
    }
  }
  if (ans) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
