fun main(args:Array<String>) {
    val (h, w) = readLine()?.split(" ")?.map { it.toInt() } ?: return
    val sList: List<CharArray> = (0 until h).map {
        readLine()?.toCharArray()!!
    }

    for ((i, list) in sList.withIndex()) {
        for ((j, c) in list.withIndex()) {
            if (c != '#') {
                continue
            }
            if ((i > 1 && sList[i - 1][j] == '#') ||
                (i < h - 1 && sList[i + 1][j] == '#') ||
                (j > 1 && sList[i][j - 1] == '#') ||
                (j < w - 1 && sList[i][j + 1] == '#')
            ) {
                continue
            }
            println("No")
            return
        }
    }

    println("Yes")
}