fun main(args: Array<String>) {
    val (h, w) = readLine()!!.split(' ').map(String::toInt)
    val grid = (1..h).map {
        readLine()!!.toCharArray()
    }

    val d = listOf(-1 to 0, 0 to 1, 1 to 0, 0 to -1)

    for (y in (1..(h - 1))) {
        for (x in (1..(w - 1))) {
            if (grid[y][x] != '#') {
                continue
            }

            var no = true
            for ((dy, dx) in d) {
                if (y + dy !in (0..(h - 1))) {
                    continue
                }

                if (x + dx !in (0..(w - 1))) {
                    continue
                }

                if (grid[y + dy][x + dx] == '#') {
                    no = false
                    break
                }
            }

            if (no) {
                println("No")
                return
            }
        }
    }

    println("Yes")
}