object Main extends App {
  val inputs = io.Source.stdin.getLines.toIndexedSeq
  .tail.map('.' +: _.toIndexedSeq :+ '.')
  val wall = inputs(0).map(_ => '.')
  val field = wall +: inputs :+ wall
  
  private def eval(x:Int, y:Int):Boolean={
    if(field(y)(x) != '#') return true
    if(field(y)(x-1) == '#') return true
    if(field(y)(x+1) == '#') return true
    if(field(y-1)(x) == '#') return true
    if(field(y+1)(x) == '#') return true
    //println(x,y)
    return false
  }
  private def func():Boolean={
    (1 until field.size-1 ).foreach{ y =>
      (1 until field(0).size-1 ).foreach{ x =>
        if(!eval(x,y)) return false
      }
    }
    return true
  }
  val ret = if(func()) "Yes" else "No"
  println(ret)
}
