#include <bits/stdc++.h>
using namespace std;
int H, W;
bool S[52][52];
int main() {
  cin >> H >> W;
  for (int i = 1; i <= H; ++i)
    for (int j = 1; j <= W; ++j) {
      char c;
      cin >> c;
      S[i][j] = c == '#';
    }
  for (int i = 1; i <= H; ++i)
    for (int j = 1; j <= W; ++j) {
      if (S[i][j] && !S[i - 1][j] && !S[i + 1][j] && !S[i][j - 1] &&
          !S[i][j + 1]) {
        cout << "No" << endl;
      }
    }
  cout << "Yes" << endl;
  return 0;
}
