MapToPoster is a fun little project that takes open street map data and creates beautiful posters of different cities/locations. More geo projects like this, please.
iamcal.com Since May 2000
Feb 22nd: I'm not great at the dialed.gg color memory/matching game, probably due to being color blind, but it's pretty fun!
Jan 31st: I've been thinking about Logo/Turtle recently and was looking for some good Scratch-like environments for kids to get started in (besides Scratch's own Pen extension). Trinket looks interesting (as an intro to Python), but Turtle Blocks is just what I was looking for. The official hosted version is extremely slow to load for some reason, but it's open source - you can host your own copy and add extensions.
Jan 21st: Nikita's critique of the Mac OS Tahoe icons is accurate and awful. The slow enshittification of everything.
MapToPoster
2025 Reading List
Another year, another 121 books completed, or about 1 every 3 days. My 2025 reading list has a very brief review/summary of each one.
Highlights were The Thursday Murder Club by Richard Osman, Piranesi by Susanna Clarke, The Repeat Room by Jesse Ball and Little Eyes by Samanta Schweblin.
While I strive not to be, I can be pretty inconsistent in my reading pace. More books take 1 day to read than any other length of time, with 72% in 3 days or less and 93% within a week. The longest took a full 23 days (because I was on a vacation where I didn't read much).
I read much less on vacation than when I'm at home, and I read the most when I get really dug into a series I love - October was 13 books from Mick Herron's Slough House.
With ~20 years of my reading history tracked, my biggest take away is that there are still so many great books to find :)
Dec 22nd: Jeff & Sanjay recently published a bunch of performance hints, many (most? all?) of which are universally useful approaches for software engineering in general
Dec 22nd: Text editing is just much more complex than you might imagine.
Dec 9th: An interesting (hour long) video about the walk/pathing system from The Witness (and generally how difficult collision and pathing is in 3D games)
Devil Platforms
Level Devil a great little 'frustrating platformer'. I love this genre, mostly to watch, as playing is pretty frustrating [via Myles]
About
This is the personal website of Cal Henderson, Slack co-founder & CTO.
I give occasional talks, write code and sometimes articles.
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