fun main(){
    val (h, w) = readLine()!!.split(" ").map { it.toInt() }
    val s = Array(h){ readLine()!! }
    for(i in 0 until h){
        for(j in 0 until w){
            if(s[i][j] == '#'){
                var f = false
                if(i != 0){
                    f = f || s[i - 1][j] == '#'
                }
                if(j != 0){
                    f = f || s[i][j - 1] == '#'
                }
                if(i != h - 1){
                    f = f || s[i + 1][j] == '#'
                }
                if(j != w - 1){
                    f = f || s[i][j + 1] == '#'
                }
                if(!f){
                    println("No")
                    return
                }
            }

        }
    }
    println("Yes")
}