#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, n, m, f = 0;
  cin >> n >> m;
  char s[n + 5][m + 5];
  for (i = 0; i < n; i++) {
    for (j = 0; j < m; j++) {
      cin >> s[i][j];
    }
  }
  for (i = 0; i < n; i++) {
    for (j = 0; j < m; j++) {
      if ((s[i + 1][j + 1] == '#') &&
          (s[i][j + 1] == '#' || s[i + 2][j + 1] == '#' || s[i + 1][j] == '#' ||
           s[i + 1][j + 2] == '#')) {
        f = 1;
        break;
      }
    }
  }
  if (f == 1) {
    cout << "Yes" << endl;
  }
  if (f == 0) {
    cout << "No" << endl;
  }
  return 0;
}
