David Eisinger

Journal > Dispatch #32 (October 2025)

Posted 2025-10-04 under #dispatch

Claire took the kids away for a weekend with her sister and some childhood friends, all of whom have boys roughly Nico’s age. I find myself home alone for the first time in … I don’t know how long, before Nev was born almost four years ago. Strange feeling – so quiet. Not bad, just so different from my normal life. I can’t believe I used to live like this.

Copenhagen

The big highlight of September was a five-day trip to Copenhagen. We loved it: the parks, the bike infrastructure, the kid-friendliness of everything. The highlights:

And then just so many nice public parks and cafes. And feeding pigeons, randomly – that ended up being a major pastime. Highly recommended for anyone but especially if you like urban biking and/or you have young kids you want to see the world. I feel just so incredibly fortunate to be able do things like this.

3D Monk

Nev has a snake fidget toy I like to steal and make little figurines out of. I’ve long wanted to make a digital version of it, but it was an intimidating enough project that I never took action. Recently, I’ve been playing with ChatGPT Codex, an AI prompt that runs in the terminal that can directly edit computer source code, and I decided to see if it could help me make progress with this project.

My first attempt fell completely flat – I gave it a photo of the toy and a README with the desired functionality. It was able to make a program that output an image, but it wasn’t anywhere close to the desired functionality and no amount of prompting got any closer.

For my second attempt, I took a more hands-on approach: I had it define the relevant structs (point, piece, snake) and then coached it through the difficult parts (adding a piece with a given rotation, detecting collisions, etc.). Once I had the abstract points-in-space stuff nailed down, the results were pretty amazing – I had it output an image (isomorphic at first, then with perspective), then color the pieces and add lighting effects, then do a pixelated/SNES version, then animate from one configuration to another.

This was a super cool experience. There was stuff I could do (reasoning about three-dimensional shapes) that the LLM couldn’t, and stuff it could do in seconds that would have taken me hours and hours. Here’s the source code if you want to play with it, and here are some (full-color) examples.

I turned 43 in mid-September. Not much to say about that, another trip around then sun. The only striking thing about it is how many clear memories I have from 2015, and how I feel like basically the same guy now that I was then. Obviously a lot’s changed in the intervening decade, but I feel like I can relate to 33-year-old Dave in a way I can’t to, say, the 28-year-old version.

Two more weeks until my half marathon. Feeling slightly underprepared, but I think I can get three more 10+ mile runs in before then and do alright, though I’ll be surprised if I can match my time from last year. I need to make a more ambitious running calendar in 2026 – I want to maintain decent aerobic health year-round, rather than sitting on the couch for six months and then trying to get back into half-marathon shape starting in August.

With Nev at the new school and the weather cooling off, we’ve started taking the kids in by bike several days a week. This has been a great way to start and/or end the day. I’m tempted by a cargo bike like the one we had in Denmark, but the good ones cost more than my first car. I did take my e-bike into the shop for some maintenance and a few upgrades with the idea that maybe it can last until the kids are biking themselves.

Nev’s on her first soccer team, the Hamsters. Results are mixed so far, but she had a great game her last time out and scored her first goal.

A few miscellaneous recommendations:

Finally, I’ll leave you with a passage from this post that’s been rattling around my brain since I read it:

(On review: I have a particular relationship with the word want. When asked “do you want to …” I try to reserve “yes” for things I have already considered and have decided to form an intention around. And on the back end, if I find myself saying, “I want to …” but then never do it, I have sort of an existential relationship to the word: You aren’t what you say you are. You haven’t done what you said you want to do. You are what you do. And barring blockers, obstacles, and other matters of physics and circumstance, if you thought you wanted to do something, then never did it, but completely could have, can you really be said to have wanted to do it? At the very best, “not much.” I don’t think this is a popular point of view because people are increasingly suspicious of the idea that anyone actually has any agency.)

I’ve a lot of things I think I want to do, but then don’t. Maybe I need to admit to myself that I don’t really want to do them. Or, perhaps: I suck at them, and the process of getting better isn’t particularly obvious or fun.

This Month

Reading & Listening

References