Full Width 
FOCUS MODE
Shortcuts 
Sign Up 
Log In 
Articles 
Reading List More from Alex Meub
3D Printing has allowed me to be creative in ways I never thought possible. It has allowed me to create products that provide real value, products that didn’t exist before I designed them. On top of that, it’s satisfied my desire to ship products, even if the end-user is just me. Another great thing is how quickly 3D printing provides value. If I see a problem, I can design and print a solution that works in just a few hours. Even if I’m the only one who benefits, that’s enough. But sharing these creations takes the experience even further. When I see others use or improve on something I’ve made, it makes the process feel so much more worthwhile. It gives me the same feeling of fulfillment when I ship software products at work. Before mass-market 3D printing, creators would need to navigate the complexity and high costs of mass-production methods (like injection molding) even to get a limited run of a niche product produced. With 3D printing, they can transfer the cost of production to others. Millions of people have access to good 3D printers now (at home, work, school, libraries, maker spaces), which means almost anyone can replicate a design. Having a universal format for sharing 3D designs dramatically lowers the effort that goes into sharing them. Creators can share their design as an STL file, which describes the surface geometry of their 3D object as thousands of little triangles. This “standard currency” of the 3D printing world is often all that is required to precisely replicate a design. This dramatically lowers the effort that goes into sharing printable designs. The widespread availability of 3D printers and the universal format for sharing 3D designs has allowed 3D-printed products to not only exist but thrive in maker communities. This is the magic of 3D printing: it empowers individuals to solve their own problems by designing solutions while enabling others to reproduce those designs at minimal cost and effort.
Last summer, I was inspired by a computer that was built inside of a toaster that I saw at a local computer recycling store. The idea of a computer with the design of a home appliance was really appealing and so was the absurdity of it. It occurred to me that this would be a fun and creative way to integrate technology into my life. After thinking about it, I realized there’s also something visually appealing about how simple and utilitarian toasters are. I have major nostalgia for the famous After Dark screensaver and I think this is why. I knew now that I wanted to make my own attempt at a toaster/computer hybrid. I decided to do just that when I created the DataToaster 3000: a toaster NAS with two 3.5 inch hard disk docking stations built inside it. The hard disks can be easily swapped out (while powered off) without taking anything apart. It uses a Zimaboard x86-64 single board computer and even has a functional knob that controls the color of the power LED. I designed a fairly complex set of 3D-printed parts that attach to the base of the toaster and hold everything neatly in place. This allows it to be easily disassembled if I ever want to make any modifications and also hopefully makes the project easier to build for others. It’s a ridiculous thing but I really do love it. You can find the build guide on Instructables and the 3D models on Printables.
I wanted to add more hauling capacity to my bike and was looking for something compatible with my Yepp rear rack. I also use my rack with a child seat (the Yepp Maxi) which has a mechanism that allows it to attach and detach easily without sacrificing safety. I was thinking it would be great to build a Yepp compatible rear basket that could I just as quickly attach/detach from my rack. I designed a removable Yepp-rack-compatible rear basket that consists of a milk crate, some plywood for stability and a 3D printed bracket threaded for M6 bolts which hold it all together. It can be attached and removed in seconds and is very secure. 3D Printed Mounting Bracket I modeled my mounting bracket after the one on the Yepp Maxi childseat. After a few iterations I was able to make it perfectly fit. I printed it in PETG filament so it was UV resistant and then installed threaded inserts for M6 bolts to attach it to the milk crate and my rear rack. 3D Print and Build Instructions You can find the 3D print on Printables and a full build guide on Instructables.
The Yoto Mini is one of my favorite products. The team behind it deeply understands its users and put just the right set of features into a brilliantly designed package. I have no affiliation with Yoto, I’m just a happy customer with kids who love it. If you aren’t aware, Yoto is an audio platform for kids with what they call “screen-free” audio players (even though they have little pixel LED screens on them). The players are Wi-Fi enabled and support playing audio from credit card-sized NFC tags called Yoto cards. Yoto sells audio players and also licenses audio content and offers it on its platform as well. The cards themselves do not contain any audio data, just a unique ID of the audio content that is pulled from the cloud. After content is pulled on the first play, it is saved and played locally from the player after that. Yoto also supports playing podcasts and music stations without using cards. Their marketing puts a lot of emphasis on the platform being “ad-free” which is mostly true as there are never ads on Yoto cards or official Yoto podcasts. However, some of the other podcasts do advertise their content. So, what’s so great about the Yoto Mini? This concept isn’t new as there have been many examples of audio players for kids over the years. What sets it apart is how every detail of the hardware, mobile app, and exclusive content is meticulously designed and well executed. Yoto Mini Hardware The main input methods of the Yoto Mini are two orange knobs, turning the left knob controls volume and the right knob navigates chapters or tracks. Pressing the right knob instantly plays the Yoto Daily podcast and pressing it twice plays Yoto Radio (a kid-friendly music station). These actions are both configurable in the mobile app. The NFC reader slot accepts Yoto cards and instantly starts playing where you left off after you insert one. It has a high-quality speaker that can be surprisingly loud, an on/off button, a USB-C charging port, an audio output jack, and a small pixel display that shows images related to the audio content. The Yoto Mini is also surprisingly durable. My kids have dropped it many times on hard surfaces and it still basically looks as good as new. Yoto understands that the physical audio player itself is primarily used by younger kids and the design reflects this. My 3-year-old daughter was able to figure out how to turn it on/off, start listening to books using cards, and play the Yoto Daily podcast each morning which was empowering for her. This was her first technology product that she was fully capable of using without help from an adult. I can’t think of many other products that do this better. Yoto Mobile App The Yoto team understands that parents are users of this product too, mostly for managing the device and its content. Yoto has built a very good mobile experience that is tightly integrated with the hardware and provides all the features you’d want as a parent. From the app, you can start playing any of the content from cards you own on the player or your phone (nice if your kids lose a card), you can set volume limits for both night and day time, you can set alarms, and configure the shortcut buttons. You can record audio onto a blank Yoto card (which comes with the player) if your kid wants to create their own story, link it to their favorite podcast or favorite music. The app even lets you give each track custom pixel art that is displayed on the screen. Audio Content By far the most underrated feature is a daily podcast called Yoto Daily. This ad-free podcast is run by a charming British host and it is funny, entertaining, and educational. My kids (now 4 and 7) look forward to it every morning and the fact that it’s daily free content that is integrated directly into the Yoto hardware is amazing. To me, this is the killer feature, as my kids get to enjoy it every day and it’s always fresh and interesting. Yoto licenses content from child book authors, popular kid’s shows, movies, and music (recently the Beatles) which are made available in their store. I also discovered that Yoto does not seem to lock down its content with DRM. My son traded some Yoto cards with a friend and I assumed there would be some kind of transfer or de-registration process but to my surprise, they just worked without issue. Conclusion The Yoto Mini is a delightful product. The team behind it thought through every detail and made it an absolute joy to use both as a child and parent. I’m impressed at how well the Yoto team understands their users and prioritizes simplicity and ease of use above all else.
More in programming
A deep dive into the Action Cache, the CAS, and the security issues that arise from using Bazel with a remote cache but without remote execution
The first in a series of posts about doing things the right way
(I present to you my stream of consciousness on the topic of casing as it applies to the web platform.) I’m reading about the new command and commandfor attributes — which I’m super excited about, declarative behavior invocation in HTML? YES PLEASE!! — and one thing that strikes me is the casing in these APIs. For example, the command attribute has a variety of values in HTML which correspond to APIs in JavaScript. The show-popover attribute value maps to .showPopover() in JavaScript. hide-popover maps to .hidePopover(), etc. So what we have is: lowercase in attribute names e.g. commandfor="..." kebab-case in attribute values e.g. show-popover camelCase for JS counterparts e.g. showPopover() After thinking about this a little more, I remember that HTML attributes names are case insensitive, so the browser will normalize them to lowercase during parsing. Given that, I suppose you could write commandFor="..." but it’s effectively the same. Ok, lowercase attribute names in HTML makes sense. The related popover attributes follow the same convention: popovertarget popovertargetaction And there are many other attribute names in HTML that are lowercase, e.g.: maxlength novalidate contenteditable autocomplete formenctype So that all makes sense. But wait, there are some attribute names with hyphens in them, like aria-label="..." and data-value="...". So why isn’t it command-for="..."? Well, upon further reflection, I suppose those attributes were named that way for extensibility’s sake: they are essentially wildcard attributes that represent a family of attributes that are all under the same namespace: aria-* and data-*. But wait, isn’t that an argument for doing popover-target and popover-target-action? Or command and command-for? But wait (I keep saying that) there are kebab-case attribute names in HTML — like http-equiv on the <meta> tag, or accept-charset on the form tag — but those seem more like legacy exceptions. It seems like the only answer here is: there is no rule. Naming is driven by convention and decisions are made on a case-by-case basis. But if I had to summarize, it would probably be that the default casing for new APIs tends to follow the rules I outlined at the start (and what’s reflected in the new command APIs): lowercase for HTML attributes names kebab-case for HTML attribute values camelCase for JS counterparts Let’s not even get into SVG attribute names We need one of those “bless this mess” signs that we can hang over the World Wide Web. Email · Mastodon · Bluesky
Greetings everyone! You might have noticed that it's September and I don't have the next version of Logic for Programmers ready. As penance, here's ten free copies of the book. So a few months ago I wrote a newsletter about how we use nondeterminism in formal methods. The overarching idea: Nondeterminism is when multiple paths are possible from a starting state. A system preserves a property if it holds on all possible paths. If even one path violates the property, then we have a bug. An intuitive model of this is that for this is that when faced with a nondeterministic choice, the system always makes the worst possible choice. This is sometimes called demonic nondeterminism and is favored in formal methods because we are paranoid to a fault. The opposite would be angelic nondeterminism, where the system always makes the best possible choice. A property then holds if any possible path satisfies that property.1 This is not as common in FM, but it still has its uses! "Players can access the secret level" or "We can always shut down the computer" are reachability properties, that something is possible even if not actually done. In broader computer science research, I'd say that angelic nondeterminism is more popular, due to its widespread use in complexity analysis and programming languages. Complexity Analysis P is the set of all "decision problems" (basically, boolean functions) can be solved in polynomial time: there's an algorithm that's worst-case in O(n), O(n²), O(n³), etc.2 NP is the set of all problems that can be solved in polynomial time by an algorithm with angelic nondeterminism.3 For example, the question "does list l contain x" can be solved in O(1) time by a nondeterministic algorithm: fun is_member(l: List[T], x: T): bool { if l == [] {return false}; guess i in 0..<(len(l)-1); return l[i] == x; } Say call is_member([a, b, c, d], c). The best possible choice would be to guess i = 2, which would correctly return true. Now call is_member([a, b], d). No matter what we guess, the algorithm correctly returns false. and just return false. Ergo, O(1). NP stands for "Nondeterministic Polynomial". (And I just now realized something pretty cool: you can say that P is the set of all problems solvable in polynomial time under demonic nondeterminism, which is a nice parallel between the two classes.) Computer scientists have proven that angelic nondeterminism doesn't give us any more "power": there are no problems solvable with AN that aren't also solvable deterministically. The big question is whether AN is more efficient: it is widely believed, but not proven, that there are problems in NP but not in P. Most famously, "Is there any variable assignment that makes this boolean formula true?" A polynomial AN algorithm is again easy: fun SAT(f(x1, x2, …: bool): bool): bool { N = num_params(f) for i in 1..=num_params(f) { guess x_i in {true, false} } return f(x_1, x_2, …) } The best deterministic algorithms we have to solve the same problem are worst-case exponential with the number of boolean parameters. This a real frustrating problem because real computers don't have angelic nondeterminism, so problems like SAT remain hard. We can solve most "well-behaved" instances of the problem in reasonable time, but the worst-case instances get intractable real fast. Means of Abstraction We can directly turn an AN algorithm into a (possibly much slower) deterministic algorithm, such as by backtracking. This makes AN a pretty good abstraction over what an algorithm is doing. Does the regex (a+b)\1+ match "abaabaabaab"? Yes, if the regex engine nondeterministically guesses that it needs to start at the third letter and make the group aab. How does my PL's regex implementation find that match? I dunno, backtracking or NFA construction or something, I don't need to know the deterministic specifics in order to use the nondeterministic abstraction. Neel Krishnaswami has a great definition of 'declarative language': "any language with a semantics has some nontrivial existential quantifiers in it". I'm not sure if this is identical to saying "a language with an angelic nondeterministic abstraction", but they must be pretty close, and all of his examples match: SQL's selects and joins Parsing DSLs Logic programming's unification Constraint solving On top of that I'd add CSS selectors and planner's actions; all nondeterministic abstractions over a deterministic implementation. He also says that the things programmers hate most in declarative languages are features that "that expose the operational model": constraint solver search strategies, Prolog cuts, regex backreferences, etc. Which again matches my experiences with angelic nondeterminism: I dread features that force me to understand the deterministic implementation. But they're necessary, since P probably != NP and so we need to worry about operational optimizations. Eldritch Nondeterminism If you need to know the ratio of good/bad paths, the number of good paths, or probability, or anything more than "there is a good path" or "there is a bad path", you are beyond the reach of heaven or hell. Angelic and demonic nondeterminism are duals: angelic returns "yes" if some choice: correct and demonic returns "no" if !all choice: correct, which is the same as some choice: !correct. ↩ Pet peeve about Big-O notation: O(n²) is the set of all algorithms that, for sufficiently large problem sizes, grow no faster that quadratically. "Bubblesort has O(n²) complexity" should be written Bubblesort in O(n²), not Bubblesort = O(n²). ↩ To be precise, solvable in polynomial time by a Nondeterministic Turing Machine, a very particular model of computation. We can broadly talk about P and NP without framing everything in terms of Turing machines, but some details of complexity classes (like the existence "weak NP-hardness") kinda need Turing machines to make sense. ↩
The 2025 edition of the TokyoDev Developer Survey is now live! If you’re a software developer living in Japan, please take a few minutes to participate. All questions are optional, and it should take less than 10 minutes to complete. The survey will remain open until September 30th. Last year, we received over 800 responses. Highlights included: Median compensation remained stable. The pay gap between international and Japanese companies narrowed to 47%. Fewer respondents had the option to work fully remotely. For 2025, we’ve added several new questions, including a dedicated section on one of the most talked-about topics in development today: AI. The survey is completely anonymous, and only aggregated results will be shared—never personally identifiable information. The more responses we get, the deeper and more meaningful our insights will be. Please help by taking the survey and sharing it with your peers!
