#include<bits/stdc++.h>
using namespace std;
#define FOR(i,l,r) for(long long i=(l);i<(r);++i)
#define REP(i,n) FOR(i,0,n)
#define int long long
#define pb push_back
#define mp make_pair
const int MOD=1e9+7;
const int INF=1e15;

signed main(){
    int H,W;cin>>H>>W;
    char A[H][W];
    REP(i,H){
        REP(j,W)cin>>A[i][j];
    }
    bool ok=true;
    REP(i,H){
        REP(j,W){
            if(A[i][j]=='#'&&(i-1<=0||A[i-1][j]=='.')&&(j-1<=0||A[i][j-1]=='.')&&(i+1>=H||A[i+1][j]=='.')&&(j+1>=W||A[i][j+1]=='.')){
                ok=false;
            }
        }
    }
  	if(H==1&&W==1)ok=false;
    if(ok)cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
}