#include <bits/stdc++.h>
using namespace std;
char s[60][60];
int h, w;
bool judge(int r1, int w1) {
  int t = 0;
  if (r1 - 1 > 0 && s[r1 - 1][w1] == '#') t++;
  if (r1 + 1 < h && s[r1 + 1][w1] == '#') t++;
  if (w1 - 1 > 0 && s[r1][w1 - 1] == '#') t++;
  if (w1 + 1 < w && s[r1][w1 + 1] == '#') t++;
  if (t == 0)
    return 0;
  else
    return 1;
}
int main() {
  while (cin >> h >> w) {
    int flag = 1;
    for (int i = 0; i < h; i++) cin >> s[i];
    if (h == 1 && w == 1 && s[0][0] == '.') {
      cout << "Yes" << endl;
      continue;
    }
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        if (s[i][j] == '#') {
          if (judge(i, j) == 0) {
            flag = 0;
            break;
          }
        }
      }
    }
    if (flag)
      cout << "Yes" << endl;
    else
      cout << "No" << endl;
  }
  return 0;
}
