import java.util.*

fun main(args: Array<String>) {
    Scanner(System.`in`).use { sc ->
        val h = sc.nextInt()
        val w = sc.nextInt()

        val src = sc.asSequence().take(h).map { it.toCharArray() }.toList()
        for (x in 0 until w) {
            for (y in 0 until h) {
                if (src[y][x] == '#') {
                    if (listOf(0 to 1, 0 to -1, 1 to 0, -1 to 0).none { entry ->
                            val (xd, yd) = entry
                            y + yd in 0 until h && x + xd in 0 until w && src[y + yd][x + xd] == '#'
                    }) {
                        println("No")
                        return
                    }
                }
            }
        }
        println("Yes")
    }
}