#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  char field[60][60] = {""};
  bool flag = false;
  cin >> h >> w;
  for (int i = 1; i <= h; ++i) {
    for (int j = 1; j <= w; ++j) {
      cin >> field[i][j];
    }
  }
  for (int k = 1; k <= h; ++k) {
    for (int i = 1; i <= w; ++i) {
      if (field[k][i] == '#' && field[k + 1][i] == '.' &&
          field[k - 1][i] == '.' && field[k][i + 1] == '.' &&
          field[k][i - 1] == '.') {
        flag = true;
      }
    }
  }
  if (flag) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
