#include <bits/stdc++.h>
using namespace std;
int main() {
  int H;
  int W;
  cin >> H >> W;
  char board[H][W];
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; i++) {
      cin >> board[i][j];
    }
  }
  const int dx[4] = {1, 0, -1, 0};
  const int dy[4] = {0, 1, 0, -1};
  string answer = "Yes";
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (board[i][j] == '.') continue;
      bool adjacentExist;
      for (int k = 0; k < 4; k++) {
        int ni = i + dy[k];
        int nj = j + dx[k];
        if (ni < 0 || H <= ni) continue;
        if (nj < 0 || W <= nj) continue;
        if (board[ni][nj] == '#') {
          adjacentExist = true;
          break;
        }
      }
      if (adjacentExist == false) answer = "No";
    }
  }
  cout << answer << endl;
  return 0;
}
