Before you complain about the notation, consider carefully whether it can be improved without losing accuracy :-)

For example, I don't like the output of "Parent Tree", but it's a necessary evil. The output tends to look better on real-life data than on contrieved examples though.

The "Dog Kennel" tests aren't inconsistent btw. Consider that [] copies the glob while capture() doesn't. That means the glob inside [] is an anonymous copy of *dogs, not the real thing.

Here's the output of your snippet:

        [
           [$L001, $L002, $L003],
$L001:     undef,
$L002:     undef,
$L003:     undef
        ]
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