#include <bits/stdc++.h>
using namespace std;
bool check_masu(char s[52][52], int h, int w) {
  return s[h - 1][w] == '#' || s[h + 1][w] == '#' || s[h][w - 1] == '#' ||
         s[h][w + 1] == '#';
}
void answer1() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  int H, W;
  cin >> H >> W;
  char s[52][52] = {};
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      cin >> s[i][j];
    }
  }
  bool is_ok = true;
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      if (s[i][j] == '#' && !check_masu(s, i, j)) {
        cout << i << ":" << j << endl;
        is_ok = false;
        break;
      }
    }
    if (!is_ok) {
      break;
    }
  }
  if (is_ok) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
}
int main() { answer1(); }
