#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  string S[55][55], temp;
  cin >> H >> W;
  for (int j = 0; j < H; j++) {
    cin >> temp;
    for (int i = 0; i < W; i++) {
      S[i][j] = temp[i];
    }
  }
  bool can = 0;
  for (int j = 0; j < H; j++) {
    for (int i = 0; i < W; i++) {
      if (S[i][j] == "#") {
        for (int l = -1; l < 2; l++) {
          for (int k = -1; k < 2; k++) {
            if (i - k >= 0 && j - l >= 0 && S[i - k][j - l] == "#" &&
                i - k != 0 && j - i != 0) {
              can = 1;
              break;
            } else {
              can = 0;
            }
          }
        }
      }
    }
  }
  if (can)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
