val rot = fn(s, key) {
    cp2s map(s2cp(s), by=fn(c) { rotate(rotate(c, distance=key, range='a'..'z'), distance=key, range='A'..'Z') })
}

val s = "A quick brown fox jumped over something, you know."
val key = 3

writeln " original: ", s
writeln "encrypted: ", rot(s, key)
writeln "decrypted: ", rot(rot(s, key), -key)