Mozilla's RR (continued by Pernosco) is one of the projects that blew my mind. The ability to record any program execution and debug it later is fascinating.

rr-project.org

ADEPT Method for technical writing: start with an Analogy, add a Diagram, show an Example, give a Plain-English explanation, and then go Technical. I used it in my write-ups at work, and it's fantastic for introducing complex ideas to a broader audience!

betterexplained.com/articles/ade...

TrueSkill (or patent-free OpenSkill): rating systems with implementations in many languages that help rate players through solo or team matches. No restrictions on team count or players per team.

You may have heard about Lean 4 last year, even if you're not into math. First, Terence Tao used Lean 4 to discover a problem in his formalized proof: mathstodon.xyz/@tao/1112877.... Next, DeepMind used it to make AI solve mathematical Olympiad problems.

While I'm sharing gems one by one, I've made the complete list public. You can see the entire collection here: dynalist.io/d/vNwMcdFKse...

If I write down any French address by ear, no Levenshtein distance will help me find the correct spelling. Metaphone/Soundex algorithms map similar-sounding words into the same phonetic code: en.wikipedia.org/wiki/Metaphone

LD_PRELOAD (or DYLD_INSERT_LIBRARIES on macOS) is a feature that lets you intercept any library or system call and replace it with your own version without touching the original code. It comes in handy while debugging or while running tests on CI.

Next up, a bit more obscure and probably better known from LeetCode problems rather than actual use: Gray Code - en.wikipedia.org/wiki/Gray_code - a math trick to make two consecutive numbers differ by only one bit.

I've been treating tech news (HN, lobste.rs, ...) like meditation - read, feel the dopamine hit, and move on. Then, I started making bookmarks and organizing them — time to share, one by one, the gems that stood the test of time.