#include <bits/stdc++.h>
#define itn int
#define rep(i, n) for (int i = 0; i < n; i++)
#define MOD 1000000007
using namespace std;
typedef long long ll;

const ll INF = 1LL << 60;

int main(){
    int h,w;
    cin >> h >> w;
    vector<vector<int>> v(vector<int>(50));
    rep(i,h){
        rep(j,w){
            cin >> v[i][j];
        }
    }
    rep(i,h){
        rep(j,w){
            if(v[i][j]=='#'&&v[i][j+1]=='.'&&v[i][j-1]=='.'&&v[i+1][j]=='.'&&v[i-1][j]=='.'){
                cout << "No" << endl;
                retunr 0;
            }
        }
    }
    cout << "Yes" << endl;
}
