fun main(args: Array<String>) {
    val (H, W) = listOfIntg()
    val S = Array(H) { next().map { if(it == '#') 1 else 0 }.toIntArray() }
    for (h in 0 until H) {
        for (w in 0 until W) {
            if (S[h][w] == 1) {
                var f = false
                if (w >= 1 && S[h][w - 1] == 1) f = true
                if (w < W - 1 && S[h][w + 1] == 1) f = true
                if (h >= 1 && S[h - 1][w] == 1) f = true
                if (h < H - 1 && S[h + 1][w] == 1) f = true
                if (!f) {
                    println("No")
                    return
                }
            }
        }
    }
    println("Yes")
}

fun next() = readLine()!!
fun nextInt() = next().toInt()
fun listOfString() = next().split(" ")
fun listOfIntg(d: Int = 0) = listOfString().map { it.toInt() + d }
