def main():
    # 下、右、上、左
    dy = [1, 0, -1, 0]
    dx = [0, 1, 0, -1]
    H, W = map(int, input().split())
    s = ["." * (W + 2)]
    s += ["." + input() + "." for i in range(H)]
    s.append("." * (W + 2))
    print(s)
    for y in range(1, H + 1):
        for x in range(1, W + 1):
            if s[y][x] == "#" and s[y + dy[0]][x + dx[0]] == "."\
                    and s[y + dy[1]][x + dx[1]] == "."\
                    and s[y + dy[2]][x + dx[2]] == "."\
                    and s[y + dy[3]][x + dx[3]] == ".":
                print("No")
                return
    print("Yes")
    return


main()
