import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int h = sc.nextInt();
		int w = sc.nextInt();
		char[][] mass = new char[h][w];
		String line = sc.nextLine();

		for (int i = 0; i < h; i++) {
			line = sc.nextLine();
			for (int x = 0; x < w; x++) {
				if (line.charAt(x) == '#') {
					mass[i][x] = 1;
				}
			}
		}
		String ans = "Yes";

		for (int i = 0; i < h; i++) {
			for (int x = 0; x < w; x++) {
				boolean yes = false;

				// 左のマス
				if (x != 0) {
					if (mass[h][x - 1] == 1)
						yes = true;
				}
				// 右のマス
				if (x != w - 1) {
					if (mass[h][x + 1] == 1)
						yes = true;
				}

				// 上のマス
				if (i != 0) {
					if (mass[h - 1][x] == 1)
						yes = true;
				}

				// 下のマス
				if (i != h - 1) {
					if (mass[h + 1][x] == 1)
						yes = true;
				}

				if (yes) {
					ans = "No";
				}
			}
		}

		System.out.println(ans);

	}
}
