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