#include<bits/stdc++.h>
using namespace std;
char s[100];
int mymap[100][105];
int main(){
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>s+1;
		for(int j=1;j<=m;j++){
			if(s[j]=='#'){
				mymap[i][j]=1;
			}
		}
	}
	int flag=0;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			if(mymap[i][j]){
				if(!mymap[i-1][j]&&!mymap[i+1][j]&&!mymap[i][j-1]&&!mymap[i][j+1]){
					flag=1;
				}
			}
		}
	}
	if(flag){
		cout<<"No"<<endl;
	}else{
		cout<<"Yes"<<endl;
	}
	return 0;
}