Problem:
Print a Frame

Draw a frame which has a height of H cm and a width of W cm. For example, the following figure shows a frame which has a height of 6 cm and a width of 10 cm.

##########
#........#
#........#
#........#
#........#
##########

Input

The input consists of multiple datasets. Each dataset consists of two integers H and W separated by a single space.

The input ends with two 0 (when both H and W are zero).

Output

For each dataset, print the frame made of '#' and '.'.

Print a blank line after each dataset.

Constraints

3 ≤ H ≤ 300

3 ≤ W ≤ 300

Sample Input

3 4
5 6
3 3
0 0

Sample Output

####
#..#
####

######
#....#
#....#
#....#
######

###
#.#
###

Solution in Scala (judge verdict: Accepted)

object Main {
  def main(args:Array[String]): Unit = {
    Iterator.continually(readLine())
      .map(s => {
        val xs = s.split(" ").map(_.toInt)  
        (xs(0), xs(1))
      })
      .takeWhile{
        case (0,0) => false
        case _ => true
      }
      .foreach(xs => {
        val h = xs._1
        val w = xs._2
       
        var st = ""
        for (i <- 1 to h){
          if (i == 1 || i == h) st += printWall(1 to w)("#") + "\n"
          else st += printVoid(1 to w)("#")(".") + "\n"
        }
        println(st)
      })
  }

  def printWall(r:Range)(wall:String): String = {
    r.foldLeft("")((a, _) => a + wall )
  }

  def printVoid(r:Range)(wall:String)(void:String): String = {
    r.foldLeft(""){
      case (a, 1) => a + wall    
      case (a, r.end) => a + wall
      case (a, _) => a + void
    }
  }
}