#include <iostream>

using namespace std;

int main(void){
	char map[52][52];

	int h, w;

	for (int i = 0; i < 51; i++){
		for (int j = 0; j < 51; j++){
			map[i][j] = '.';
		}
	}

	cin >> h >> w;
	for (int i = 1; i < h + 1; i++){
		for (int j = 1; j < w + 1; j++){
			cin >> map[i][j];
		}
	}

	int ok = 1;

	for (int i = 1; i < h + 1; i++){
		for (int j = 1; j < w + 1; j++){
			if (map[i][j] == '#'){
				if (map[i-1][j] == '.' && map[i+1][j] == '.' && map[i][j-1] == '.' && map[i][j+1] == '.')
					ok = 0;
		}
	}

	if (ok)
		cout << "Yes" << endl;
	else 
		cout << "No" << endl;
}