#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  int stmp[H][W];
  int count = 0;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      char t;
      char v = '#';
      cin >> t;
      if (t == v) {
        stmp[i][j] = 1;
      } else {
        stmp[i][j] = 0;
      }
    }
  }
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (stmp[i][j] == 1) {
        if (stmp[i + 1][j] + stmp[i - 1][j] + stmp[i][j + 1] + stmp[i][j - 1] <=
            0) {
          count++;
        }
      }
    }
  }
  if (count > 0) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
  return 0;
}
