#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
int main() {
  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  for (int i = 0; i < h; i++) {
    cin >> s[i];
  }
  bool can = true;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (s[i][j] == '.') break;
      bool can2 = false;
      for (int d = 0; d < 4; d++) {
        int ni = i + dy[d];
        int nj = j + dx[d];
        if (ni < 0 or i >= h) continue;
        if (nj < 0 or j >= w) continue;
        if (s[ni][nj] == '#') can2 = true;
      }
      if (!can2) {
        can = false;
      }
    }
  }
  if (can)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
