fun main(args: Array<String>) {
    val iLine = readLine()!!.split(" ").map(String::toInt)
    val numH = iLine[0]
    val numW = iLine[1]
    var result = "Yes"
    val paintModel = mutableListOf<List<String>>()

    for(i in 0 until numH){
        paintModel.add(readLine()!!.split("").drop(1).dropLast(1))
    }

    run loop@{
        for(i in 0 until numH){
            for(j in 0 until numW){
                if(paintModel[i][j] == "#"){
                    var cond1 = false
                    var cond2 = false
                    var cond3 = false
                    var cond4 = false
                    if(i < 1 || paintModel[i - 1][j] == "."){
                        cond1 = true
                    }
                    if(j < 1 || paintModel[i][j - 1] == "."){
                        cond2 = true
                    }
                    if(i >= numH - 1 || paintModel[i + 1][j] == "."){
                        cond3 = true
                    }
                    if(j >= numW - 1 || paintModel[i][j + 1] == "."){
                        cond4 = true
                    }
                    if(cond1 && cond2 && cond3 && cond4){
                        result = "No"
                        return@loop
                    }

                }
            }
        }
    }

    println(result)
}