fun main(args: Array<String>) {
    val (h, w) = readLine()!!.split(' ').map(String::toInt)
    var ret = true
    val canvas = (1..h).map { readLine()!! }
    outside@ for ((i, ss) in canvas.withIndex()){
        inside@ for ((j, s) in ss.withIndex()) {
            if (s == '#') {
                if (i - 1 > 0 && canvas[i - 1][j] == '#') {
                    continue@inside
                }
                if (i + 1 < h && canvas[i + 1][j] == '#') {
                    continue@inside
                }
                if (j - 1 > 0 && canvas[i][j - 1] == '#') {
                    continue@inside
                }
                if (j + 1 < w && canvas[i][j + 1] == '#') {
                    continue@inside
                }
                ret = false
                break@outside
            }
        }
    }
    print(if (ret) "Yes" else "No")
}