fun main(args: Array<String>) {
    abc096c()
}

// 上下左右が`.`である`#`のマスが無ければ可
fun abc096c() {
    val (h, w) = readLine()!!.split(" ").map { it.toInt() }

    val sList = (1..h).map { readLine()!!.toCharArray().map { it == '#' }.toBooleanArray() }

    val answer = sList.mapIndexed { si, booleans ->
        booleans.mapIndexed { bi, b ->
            if (b) {
                val above = if (si - 1 >= 0) sList[si - 1][bi] else false
                val below = if (si + 1 <= h - 1) sList[si + 1][bi] else false
                val right = if (bi + 1 <= w - 1) booleans[bi + 1] else false
                val left = if (bi - 1 >= 0) booleans[bi - 1] else false
                above || below || right || left
            } else true
        }
    }.flatten().all { it }.let { if (it) "Yes" else "No" }

    println(answer)
}
