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