update readme

Author: narimiran

README.md

@@ -13,12 +13,13 @@ All my Advent of Code repos:
 * [AoC 2022 in Python, Clojure](https://github.com/narimiran/AdventOfCode2022)
 * [AoC 2023 in Clojure](https://github.com/narimiran/AdventOfCode2023)
 * [AoC 2024 in Clojure (Clerk notebooks), Python, Elixir](https://github.com/narimiran/aoc2024)
-* [AoC 2025 in Clojure (Clerk notebooks)](https://github.com/narimiran/aoc2025) (this repo)
+* [AoC 2025 in Clojure (Clerk notebooks), Common Lisp](https://github.com/narimiran/aoc2025) (this repo)
 
 
  
 
 This year it is a Clojure time, again.
+(May 2026 EDIT: And a Common Lisp time, for the first time ever. See below.)
 
 Last year's experiment with [Clerk notebooks](https://clerk.vision) was a success
 (IMO; you can see [my AoC 2024 notebooks](https://narimiran.github.io/aoc2024) for yourself),
@@ -42,3 +43,19 @@ It is the best to _not_ read the raw code in this repo.
 Instead, read the notebooks.
 
 The notebooks are available at: https://narimiran.github.io/aoc2025
+
+
+
+### Common Lisp
+
+Common Lisp solutions were written in May 2026 and are loosely based on my existing Clojure solutions.
+This is my first time using Common Lisp: if you have any advice how to improve the solutions and/or write them more idiomatically, I would love to hear it - please open an issue.
+
+The solutions are in the [`lisp/src``](lisp/src) directory.
+To run them (this is mostly a note to myself, so I don't forget):
+
+- open a REPL
+- run `(ql:quickload "aoc")`
+- run `(in-package #:aoc)`
+- now, for each day there is a function which runs both parts, e.g. `(day01)`, `(day11)`, etc.
+- to get some evaluation statistics, use `(time (day05))`