#include <iostream>
using namesace std;

char C[64][64], int H, W, count=0

int main(void) {

	cin >> H >> W;
	for (int i = 1; i <= H; i++) {
		for (int i = 1; i <= W; i++) {
			>> C[i][j];
		}
		for (int i = 1; i <= H; i++) {
			for (int j = 1; j <= W; j++) {
				if (C[i][j] == '#' && C[i - 1][j] == '#' && C[i + 1][j] == '#' && C[i + 1][j] == '#' && C[i][j + 1] == '#') {
					count++;
					break;
				}
			}
		}
	}
	if (count == 0) {
		cout << "Yes" << endl;
	}
	else {
		cout << "No" << endl;
	}
}