#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  char s[51][51];
  bool ans = true, tmp;
  cin >> H >> W;
  for (int i = 0; i < H; i++)
    for (int j = 0; j < W; j++) cin >> s[i][j];
  for (int i = 0; i < H; i++)
    for (int j = 0; j < W; j++)
      if (s[i][j] == '#') {
        tmp = false;
        tmp = tmp || (i - 1 >= 0 && s[i - 1][j] == '#');
        tmp = tmp || (i + 1 <= H && s[i - 1][j] == '#');
        tmp = tmp || (j - 1 >= 0 && s[i][j - 1] == '#');
        tmp = tmp || (j + 1 < W && s[i][j + 1] == '#');
        ans = tmp;
      }
  cout << (ans ? "Yes" : "No") << endl;
}
