encryption.scala

def split[A](chars: List[A], n: Int): List[List[A]] = {
  if (chars.isEmpty) List()
  else chars.take(n) :: split[A](chars.drop(n), n)
}

def encrypt_rec(chars: List[List[Char]]): List[List[Char]] = {
  if (chars.isEmpty) Nil
  else {
    val cs = chars.filter(_.isEmpty == false)
    cs.map(_.head) :: encrypt_rec(cs.map(_.tail))
  }
}

def encrypt(s: String): String = {
  val chars = s.toList.filter(_ != ' ')
  val len = math.ceil(math.sqrt(chars.length)).toInt
  encrypt_rec(split[Char](chars, len)).map(_.mkString).reduceLeft(_ + ' ' + _)
}

println(encrypt("if man was meant to stay on the ground god would have given us roots"))