#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <bitset>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef long long LL;

typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<string, int> P;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a); i<(b); i++)
#define REP(i,n)  for(int i=0; i<(n); i++)

//constant
//--------------------------------------------
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
const LL MOD = 1e9+7; 
//vector <vector<int>> x(20, vector<int> (20)), y(20,vector<int> (20));
/*int counter_1 (int x) {
    if(x == 0) return 0;
    return counter_1(x >> 1) + (x & 1);
}*/

//int Counter(int x)
/*int factorial(int n) {
    if (n > 0) {
        return n * factorial(n - 1);
    } else {
        return 1;
    }
}*/
int factorial(int n) {
    if (n > 0) {
        return n * factorial(n - 1);
    } else {
        return 1;
    }
}
int main(){
    int h, w;
    cin >> h >> w;
    vector<vector<char>> s(h, vector<char>(w));
    REP(i, h){
        REP(j, w){
            cin >> s[i][j];
        }
    }
    bool flg = true;
    FOR(i, 1, h-1){
        FOR(j, 1, w-1){
            if(s[i][j]=='#'){
                if(s[i+1][j]=='.'&&s[i-1][j]=='.'&&s[i][j+1]=='.'&&s[i][j-1]=='.') {
                flg = false;
                break;
                }
            }
        }
        if(flg==false) break;
    }
    if(s[0][0]=='#'){
        if(s[0][1]=='.'&&s[1][0]=='.') flg = false;
    }
    if(s[0][w-1]=='#'){
        if(s[0][w-2]=='.'&&s[1][w-1]=='.') flg = false;
    }
    if(s[h-1][0]=='#'){
        if(s[h-2][0]=='.'&&s[h-1][1]=='.') flg = false;
    }
    if(s[h-1][w-1]=='#'){
        if(s[h-2][w-1]=='.'&&s[h-1][w-2]=='.') flg = false;
    }
    FOR(i, 1, w-1){
        if(s[0][i]=='#'){
            if(s[0][i-1]=='.'&&s[0][i+1]=='.'&&s[1][i]=='.') {
                flg = false;
                break;
            }
        }
        if(s[h-1][i]=='#'){
            if(s[h-1][i-1]=='.'&&s[h-1][i+1]=='.'&&s[h-2][i]=='.') {
                flg = false;
                break;
            }
        }
    }
    FOR(i, 1, h-1){
        if(s[i][0]=='#'){
            if(s[i-1][0]=='.'&&s[i+1][0]=='.'&&s[i][1]=='.') {
                flg = false;
                break;
            }
        }
        if(s[i][w-1]=='#'){
            if(s[i+1][w-1]=='.'&&s[i-1][w-1]=='.'&&s[i][w-2]=='.') {
                flg = false;
                break;
            }
        }
    }
     if(flg==true) cout << "Yes" << endl;
       else {
           cout << "No" << endl;
        }
}
    




Measured memory_bytes: 256