fun main(args : Array<String>) {
    val (h, w) = readLine()!!.split(" ").map { it.toInt() }
    val ss = Array(h) { readLine()!! }

    for (i in 0 until h) {
        inner@for (j in 0 until w) {
            val s = ss[i][j]
            if (s == '.') {
                continue@inner
            }

            if (j > 0 && ss[i][j-1] == '#') {
                continue@inner
            } else if (j < w-1 && ss[i][j+1] == '#') {
                continue@inner
            } else if (i > 0 && ss[i-1][j] == '#') {
                continue@inner
            } else if (i < h-1 && ss[i+1][j] == '#') {
                continue@inner
            }

            println("No")
            return
        }
    }

    println("Yes")
}