#include <bits/stdc++.h>
using namespace std;

/* #pragma */
/*
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
*/

/*alias*/
#define F first
#define S second

#define y0 y3487465
#define y1 y8687969
#define j0 j1347829
#define j1 j234892
#define next asdnext
#define prev asdprev
#define itn int

/*template*/
template<class T>inline bool amax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
template<class T>inline bool amin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; }

/* func */
int GCD(int a,int b){return b?GCD(b,a%b):a;}
long long GCD(long long a, long long b){return b ? GCD(b, a%b) : a;}
int LCM(int a, int b){return a * b / GCD(a, b);}
long long LCM(long long a, long long b){return a * b / GCD(a, b);}

/*struct*/
struct aaa {
	aaa() {
		cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20);
	};
}aaaaaaa;

/* const */
const int INF = 1001001001;
const long long LINF = 1001001001001001001ll;
const int MOD = 1e9 + 7; //10^9
const double EPS = 1e-9;
//const int dx[] = { 1, 1, 0, -1, -1, -1, 0, 1 }, dy[] = { 0, 1, 1, 1, 0, -1, -1, -1 };
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
//Counterclockwise from the 6o'clock direction
//Take the x-axis downward and the y-axis right

//#define int long long

//g++ -std=c++14 -Wall --pedantic-errors -o template template.cpp
//g++ -std=c++14 -Wall --pedantic-errors template.cpp
//chcp 65001

signed main()
{
	int h,w; cin >> h >> w;

	vector<string> c(h+1);

int cnt{};
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= W; j++) cin >> c[i][j];
	}
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= w; j++) {
			if (c[i][j] == '#' && c[i][j - 1] != '#' && c[i - 1][j] != '#' && c[i][j + 1] != '#' && c[i + 1][j] != '#') cnt++;
		}
	}
	if (cnt == 0) cout << "Yes" << endl;
	else cout << "No" << endl;	
    return 0;
}