My Advent of Code solutions in Common Lisp

In case anyone here on this track is interested - I’ve been (trying to) solve the Advent of Code problems all in Common Lisp for the last few years (and dipping back into previous years as well).

I’m not going to say that this code Is always good (I do often try to go back and clean stuff up), and plenty of learning is going on exercise to exercise so later ones are hopefully better than earlier ones.