#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
int main() {
  int H, W;
  cin >> H >> W;
  bool flag;
  
  vector<string> board(H);
  rep(i, H) cin >> board[i];
  int di[2] = {-1, 0, 0, 1};
  int dj[2] = {0, -1, 1, 0};
  
  rep(i, H){
  	rep(j, W){
    	if(board[i][j] == '.') continue;
      	flag = false;
      	
      	for(int d=0; d<4; d++){
        	int ni = i + di[d];
          	int nj = j + dj[d];
          
          	if(ni < 0 || H <= ni) continue;
          	if(nj < 0 || W <= nj) continue;
          	if(board[i][j] = '#'){
            	flag = true;
              	break;
            }
        }
      	
      	if(flag == false) break;
    }
    if(flag == false) break;
  }
  
  if(flag) cout << "Yes" << endl;
  else cout << "No" << endl;
  
  return 0;
}