#include <bits/stdc++.h>
using namespace std;
int main() {
  long long h, w;
  cin >> h >> w;
  vector<vector<char>> s(50, vector<char>(50));
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> s[i][j];
    }
  }
  long long count = 0;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      if (s[i][j] == '#' && s[i][j - 1] == '.' && s[i - 1][j] == '.' &&
          s[i + 1][j] == '.' && s[i][j + 1] == '.') {
        count++;
      }
    }
  }
  if (count > 0) {
    cout << "No";
  } else {
    cout << "Yes";
  }
  return 0;
}
