fun main(args: Array<String>) {
    val (H, W) = readInputLine().split(" ").map{it.toInt()}
    val s = Array(H, {CharArray(W)})
    
    for (i in 0 until H) {
        s[i] = readInputLine().toCharArray()
    }
    
    for (i in 0 until H) {
        for (j in 0 until W) {
            if (s[i][j] == '.') {
                continue
            }
            if (i > 0 && s[i - 1][j] == '#') {
                continue
            }
            if (i < H - 1 && s[i + 1][j] == '#') {
                continue
            }
            if (j > 0 && s[i][j] == '#') {
                continue
            }
            if (j < W - 1 && s[i][j + 1] == '#') {
                continue
            }
            println("No")
            return
        }
    }

    println("Yes")
}

fun readInputLine(): String {
    return readLine()!!
}
