Ask HN: What useful skills can be learned through rote memorization?
I recently discovered that the algorithm to calculate the day of the week for any given date (e.g. January 1, 2000 was a Saturday) can be easily memorized and, with some practice, one can calculate the day of the week for any date in 5-10 seconds (maybe 2 seconds if you really practice).
What other useful/fun skills can be learned through rote memorization? Bonus points if you can provide a website or app to learn/practice the skill. Peg system – it's a very simple rhyming mnemonic that helps you memorize a list of 10–20 items by quickly assigning visual imagery to each number. It's more of a parlor trick than anything, but it's pretty fun. Here's the list for ten (but you can go much farther than this) 1 - A longboat rows around the spherical face of the sun each of vikings dipping their flagons into the solar flares 2 - A old man accidentally knocks over his ink pot spilling it onto his shoes 3 - An Tree ent holds a cape and taunts the uruk-hai into charging at him You'll find its trivial for somebody to call out a number and to recall the associated item. Over time you'll also find yourself getting extremely quick at it as well. The algorithm I mentioned in the OP is here: https://en.wikipedia.org/wiki/Doomsday_rule I practiced the algorithm by replacing my doomscrolling time on a trainer app (https://whattheday.com/) over the last 3 weeks. I went from taking 2-20 minutes to usually get the wrong result to about 95% accuracy in 10 seconds. This training app to teach you to play piano by ear and to sight read also got posted today: https://news.ycombinator.com/item?id=46556210 1. Rubiks cube 2. Wordle. It’s much more a game of probability than anything else so start by eliminating the most common consonants and vowels. I am averaging word selection on the third row. 3. As a typical software developer can get a better job by memorizing all the details of common digital transmission mechanisms from the specifications. It’s how I escaped JavaScript insanity. 4. You can get a gardening green thumb by memorizing plant details, knowing the chemistry of your dirt, and buying old bananas by the case for conversion into a fertilizer slurry.
Then you take the list of things (grocery list, etc) you want to quickly memorize: 1 - Sun
2 - Shoe
3 - Tree
4 - Gore
5 - Hive
6 - Sticks
7 - Heaven
8 - Gate
9 - Vine
10 - Hen
and quickly create tiny visuals for each one: 1 - Viking
2 - Ink Pot
3 - Matador
...