#include <bits/stdc++.h>
using namespace std;
const int INF = 111111111;
const long long LLINF = 1e17 + 1;
const int DX[9] = {0, 0, 1, -1, 1, 1, -1, -1, 0};
const int DY[9] = {1, -1, 0, 0, 1, -1, 1, -1, 0};
const int DIV = 1000000007;
const double PI = 3.14159265358979323846264338327950288;
int main() {
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  int H, W;
  cin >> H >> W;
  vector<string> S;
  for (int i = 0; i < H; i++) {
    string temp;
    cin >> temp;
    S.emplace_back(temp);
  }
  for (int i = 0; i < W; i++) {
    for (int j = 0; j < H; j++) {
      if (S[i][j] == '#') {
        int count = 0;
        for (int k = 0; k < 4; k++) {
          if (0 <= i + DX[k] && i + DX[k] < H && 0 <= j + DY[k] &&
              j + DY[k] < W) {
            if (S[i + DX[k]][j + DY[k]] == '#') {
              count++;
            }
          }
        }
        if (count == 0) {
          cout << "No";
          return 0;
        }
      }
    }
  }
  cout << "Yes";
}
