#include <iostream>
#include <string>
using namespace std;
int main() {
	int a, b, ans=0;
	cin >> a >> b;
	char k[50][50];
	for (int i = 0; i < a; i++) {
		for (int m = 0; m < b; m++) {
			cin >> k[i][m];
		}
	}
	for (int i = 0; i < a; i++) {
		for (int m = 0; m < b; m++) {
			if (k[i][m] == '#'&&k[i][m + 1] != '#'&&k[i][m - 1] != '#'&&k[i + 1][m] != '#'&&k[i - 1][m] != '#') ans += 1;
		}
	}
	if (ans == 0) cout << "Yes" << endl;
	else cout << "No" << endl;
}