Challenge 3: A Hash of Arrays — Possible Solution
====================================================================

use strict;
use warnings;
use feature 'say';

my %departments = (
    Engineering => ["Ada", "Grace", "Alan"],
    Marketing   => ["Bob", "Carol"],
);

foreach my $name (@{ $departments{Engineering} }) {
    say $name;
}

Output:
Ada
Grace
Alan

WHY THIS WORKS AS AN ANSWER
------------------------------
["Ada", "Grace", "Alan"] and ["Bob", "Carol"] both reuse the
chapter's own anonymous-array-reference syntax exactly — square
brackets build a new array reference directly inline, with no
separately-declared @array variable needed for each department,
matching the chapter's own %teams example structure precisely, just
with department names and employees instead of team colors and
players.

%departments is a plain hash (Chapter 4) whose values are each one of
those array references — the chapter's own "hash of arrays" shape.

$departments{Engineering} retrieves the array reference stored under
the "Engineering" key, reusing ordinary hash-value lookup from
Chapter 4. Wrapping it as @{ $departments{Engineering} } reuses the
chapter's own classic dereference syntax (@{...}) to turn that
reference back into the actual list of three names, which foreach
can then iterate over directly — equivalently, this could also be
written @{$departments{Engineering}} without the inner spaces, or
even without an explicit dereference at all in some contexts, but the
braced form here makes clear exactly what's being dereferenced and
into what shape (a list, per the @ sigil), directly answering the
challenge's request to print every employee in that one department.