object Element {
    private class ArrayElement(
	val contents: Array[String]
	) extends Element
    private class LineElement(s: String) extends Element {
	val contents = Array(s)
	override def width = s.length
	override def height = 1
    }
    private class UniformElement(
	ch: Char,
	override val width: Int,
	override val height: Int
    ) extends Element {
	private val line = ch.toString * width
	def contents = Array.make(height, line)
    }
    def elem(contents: Array[String]): Element = 
	new ArrayElement(contents)
    def elem(chr: Char, width: Int, height: Int): Element = 
	new UniformElement(chr, width, height)
    def elem(line: String): Element = 
	new LineElement(line)
}

import Element.elem
abstract class Element {
    def contents: Array[String]
    def width: Int =
	if (height == 0) 0 else contents(0).length
    def height: Int = contents.length
    def above(that: Element): Element = {
	val this1 = this widen that.width
	val that1 = that widen this.width
	elem(this1.contents ++ that1.contents)
    }
    def beside(that: Element): Element = {
	val this1 = this heighten that.height
	val that1 = that heighten this.height
	elem (
	    for ((line1, line2) <- this1.contents zip that1.contents)
	    yield line1 + line2)
    }
    def widen(w: Int): Element = 
	if (w <= width) this
	else {
	    val left = elem(' ', (w - width) / 2, height)
	    val right = elem(' ', w- width - left.width, height)
	    left beside this beside right
	}
    def heighten(h: Int): Element = 
	if (h <= height) this
	else {
	    val top = elem(' ', width, (h - height) / 2)
	    var bot = elem(' ', width, h - height - top.height)
	    top above this above bot
	}
    override def toString = contents mkString "\n"
}