#include<iostream>
#include<string>

using namespace std;

int main() {
	int H, W, ans = 0;
	char s[50][50];

	cin >> H >> W;

	for (int i = 1; i <= H; i++) {
		for (int j = 1; j <= W; j++) {
			cin >> s[i][j];
		}
	}

	for (int i = 1; i <= H; i++) {
		for (int j = 1; j <= W; j++) {
			if (s[i][j] == '#' && s[i][j - 1] == '.' && s[i][j + 1] == '.' && s[i - 1][j] == '.' && s[i + 1][j] = '.') {
				ans++;
			}
		}
	}

	if (ans == 0) {
		cout << "Yes" << endl;
	}
	else {
		cout << "No" << endl;
	}
	return 0;;
}