Kotlin: What is familiar? What is new?

Main.kt

import kotlin.text.Regex

fun makeScrambler(order: List<Int>): (String) -> String {
    fun scrambler(plainText: String): String {
        val word = plainText.toList()
        val code = order.indices.map { word[order[it] - 1] }
        return code.joinToString(
            prefix = "",
            separator = "",
            postfix = "")
    } // scrambler()
    return ::scrambler
} // makeScrambler()

// I have not used this function but
// thought it might be useful in some
// future enhancement of this program.
fun makeSuffix(n:Int):String {
    // return a string that contains
    // n X's
    return (0 until n).joinToString(
        prefix = "",
        separator = "",
        postfix = ""
    ) { "X" }
} // makeSuffix()

fun pad( blockOfLetters:String):String {
    /*
    pre-condition: length of blockOfLetters <= 5
    return blockOfLetters + how every many X's are
    needed to make a string with a length = 5
     */
    return when( blockOfLetters.length ) {
        0 -> blockOfLetters + "XXXXX"
        1 -> blockOfLetters + "XXXX"
        2 -> blockOfLetters + "XXX"
        3 -> blockOfLetters + "XX"
        4 -> blockOfLetters + "X"
        else -> blockOfLetters
    }
} // pad()

fun main() {
    // a five letter word
    val programmingLanguage = "BASIC"

    val farewellFromInstructor =
        "Thank you for choosing to study with us!"

    val fredBrooks = "A scientist builds in order to learn;" +
            "an engineer learns in order to build."

    val philipGlass =
            "A new language requires a new technique. " +
            "If what you are saying does not require a new " +
            "language, then what you are saying probably is " +
            "not new."

    // The zip code for Mount Vernon, Iowa
    // is our key for encryption.
    // Any permutation of the integers
    // 1, 2, 3, 4, 5 will work.
    val zipcode = listOf(5, 2, 3, 1, 4)

    // Choose a quotation.
    val quotation = philipGlass

    val re = Regex("\\w")
    val plainText = quotation.
      filter { re.matches(it.toString()) }.
      uppercase().
      chunked(zipcode.size).
      map { pad(it) }

    println( farewellFromInstructor )

    println(plainText)

    val encoder = makeScrambler(zipcode)
    println( plainText.map { encoder(it) } )
} // main()