On Etsy, you can buy five billion Zimbabwean dollars for a billion times less (minus one cent)
And a 50 trillion note can be bought for 30 dollars (minus two cents)
And there is also a 100 trillion note
Category: facebook
Crafting the Future of Recommender Systems: A Deep Dive into Algorithms and Implementation | September 26 2025, 21:17
I decided a while ago to write a book on recommendation algorithms. With mathematics, code examples, a repository, etc. English, of course.
Accordingly, I am looking for volunteer reviewers who are knowledgeable in the field. Also those who have experience with print-on-demand on Amazon.
There’s already about 200 pages of content. About three months of work left. Working title Recommender Algorithms in 2026: A Practitioner’s Guide. Roughly half of it is still in draft form, with the first 80 pages about 80% complete.
I’ve built a mechanism to publish in HTML and PDF simultaneously. The HTML version is fully functional, with navigation. The navigation block reflects the current section, and as you scroll, it shifts to the one in front of the reader. Clicking on a section, of course, teleports you to what you clicked on. It’s all completely automatic.
Revolutionizing Car Safety: Pre-Collision Airbag Deployment and Smart Updates in Modern Vehicles | September 24 2025, 12:54
So far, I have only one car model and brand that can deploy airbags not at the moment of impact, but a moment earlier, so that by the time of the impact, it’s not too late to do so. We’ll see what the news shows, but tests indicate that this thing works better than the traditional method. Reality might turn out to be harsher, but we’ll keep an eye on it.
It’s also interesting that the car started to receive new exciting features after purchase. I never had this experience before. What you bought it with, you lived with, and sometimes you could go to the dealership for something new, and it usually involved replacing something physical.
The previous update (not very useful to me, but maybe to someone) was about automatic detection of children and animals in the cabin. And if it turns out they were left inside while the owner left, the car does not turn off the climate control. And of course, it screams into the app that this is not a good thing to do.
Childhood Curiosity and the Mysteries of Soviet Electrical Engineering | September 23 2025, 17:00
I remember being puzzled as a child by who the idiot was that decided to make the radio plug exactly the same as the one for 220 volts. This radio plug was supposed to go into a radio socket.
As a child, I used to disassemble and “improve” almost everything electrical in the house (I hadn’t graduated to electronics yet). Of course, I got shocked many times by the outlet, but to my surprise, the old Soviet phone could also give a shock. When a call came in, the voltage in the line would jump from 12-60 volts to 120 volts 🙂
I also had an interesting experience with Christmas lights. For a younger schoolchild, it was unclear why Christmas lights could shock you since they used the same bulbs that I connected to a flat “Planeta” battery. I had to learn the technicalities 🙂 By the way, those square flat batteries have disappeared; they used to be everywhere.
Inside the High-Tech World of USB-C Cables: More Than Just Wires | September 22 2025, 22:50
It turns out USB-C cables are sometimes whole computers inside the odd form factor of a wire. Watching a video where guys from Adam Savage’s dissected an Apple Thunderbolt 4 cable ($130) using a CT scanner, explaining its internals, and comparing it to a similar cable for $12.
The cable connector contains a complex system that includes a full-fledged processor, two power supplies, and many other components. The processor splits data into multiple parallel streams and converts them into differential signals that travel through twisted, intertwined pairs of wires. The system sends two signals simultaneously, but in mirror-opposite directions. This helps protect the signal from interference (from vacuum cleaners, mobile phones, etc.). Indeed, the circuit board inside is nine-layered.
On the internal circuit board, there are interesting serpentine/wavy tracks with sizes in fractions of a millimeter. It turns out, Apple engineers intentionally made them longer to match the overall length with the neighboring longer tracks (because they include turns). This is necessary for the signals to reach the processor absolutely simultaneously, down to the nanosecond.
The cable itself inside is made up of many individually shielded smaller coaxial cables. There are more than a dozen of them.
The cheap cable lacks this smart electronics, no active components inside. It just has connectors and wires.
But the coolest thing – the guys post such scans in the video description as a link to a viewing program. There you can rotate and examine everything on your own. I’ll put it in the comments
Switching from Sony to AirPods Max: A Cautionary Tale on Counterfeits | September 22 2025, 20:44
I made a gift for myself yesterday and bought Airpods Max. I already had Sony WH1000XM3, but I didn’t quite grow to like them. They don’t perform well with multiple devices, especially Macs, and although I find the sound quality decent, I prefer the sound in the Airpods, initially thinking it was due to the codecs, which indeed are a bit chaotic. Sony supports all – SBC, AAC, aptX, aptX HD, and LDAC. Apple devices (Mac, iPhone) do not support aptX and LDAC. Of all the advanced codecs available to Sony, the only one Apple devices can utilize is AAC. Exactly the same codec found in Airpods. But the sound to the ear is noticeably different.
Regarding the new ones, I realized I would be earning an eternity plus still, of course, I decided to buy used. For popular items, if you have a lot of time, you’ll definitely find some in excellent condition and for half the price. And here’s what I found out in the process: nine out of ten “half-price” headphones are fakes. The same situation applies to Airpod earplugs. Sometimes they are of very high quality, but like any counterfeit, they have serious flaws, but as many reviews say, the average ear won’t notice the difference, as counterfeiters don’t skimp on the audio path.
Eventually, I watched a ton of videos on how to distinguish fakes from genuine ones, and managed to buy Airpods in perfect condition yesterday for $180 when their price is $500.
Interestingly, checking the serial number on Apple’s website is no longer a cure-all because they’ve learned to reuse serial numbers from stolen ones. Most importantly: never buy a sealed box. Its outer part is counterfeited such that it can only be differentiated by the slightly less neatly wrapped film. In unpacked “ears,” the differences are more noticeable. The main thing – the headphones must pair with the computer using Apple’s proprietary protocol, which the counterfeiters have not yet been able to replicate.
Popup on iPhone upon first connection: Genuine — with a “Connect” button. Fake — no button, connects via Bluetooth settings.
The material of the headphones — should be metal. Fake — plastic, because metal is more expensive to manufacture. Snap your fingers on them, there should be a specific sound (try it in the Apple Store) — but most importantly, it should be the same on both sides. On the fake, it’s different and distinct.
The material inside the box: Genuine — cardboard (possibly recycled). Fake — plastic. Although cardboard is sometimes used too. An unreliable indicator.
Wrapping of the headphones: Genuine — in paper material. Fake — in plastic or without wrapping. Also unreliable.
Case — Interior material: Genuine — soft, changes color when touched, has text. Fake — hard, does not change color. This is quite a reliable aspect, because fakes will not use more expensive leather.
Noise when shaking: Genuine — noiseless. Fake — the button moves, noise is heard. Ear cups: Genuine — strong magnets, do not fall off. Fake — weak magnets, easily detach or fall off. Screws inside the cups: Genuine — dark. Fake — silver or light. This only works if you have seen the genuine ones. The difference is impossible to describe in words.
Noise cancelation (ANC): Genuine — activates only on the head. Fake — works in any position (even on a desk). Of course, it’s also poor, but detecting this is difficult unless you have the fakes on hand.
We must also check for Spatial Audio. It requires an accelerometer inside. Of course, fakes do not install one – it’s almost unused and why unnecessarily make the design more expensive. But in Spatial, it is used (you move your head – the sound shifts back and forth).
In short, when I was traveling yesterday, I was almost sure I wouldn’t buy anything. But — I got lucky.
Speaking of the Airpods themselves, they have some drawbacks that have been known for several years. I’m okay with them. The headphones are heavier than they could be, they don’t fold as they might, they bump against the chin when worn around the neck, and it’s not very comfortable to wear them that way, the price is high (but okay for used), strange case, and the protective case is huge, half the size of a backpack. Among the very important pros for me — support for multiple devices and perfect integration with Apple devices, good noise cancellation (almost like Sony’s), premium materials, and perfect build quality.
From Opera to Oblivion: The Fascinating Journey of Lorenzo Da Ponte | September 22 2025, 18:53
We just finished watching Le Nozze di Figaro with Nadezhda in a serialized mode and today we’ll continue with Don Giovanni, also in a serialized mode, because no one has the time. So, both of these operas were written by an American 🙂 I mean the librettos. Turns out, Lorenzo Da Ponte, an Italian librettist, emigrated, naturalized in the U.S., lived here 33 years, taught Italian literature at Columbia University in New York, founded an opera theater in the USA, which became the precursor to the New York Academy of Music and the New York Metropolitan Opera. Really an interesting dude. His real name was Emanuel Conegliano. A Jew by birth, who became a Catholic priest, a friend of Casanova, and a supporter of Rousseau’s ideas. Before moving to the U.S., Da Ponte successfully juggled teaching and a small business, earning not so much from lectures as from owning a brothel for aristocrats which he maintained. In the U.S., he kept a grocery store in New Jersey and tried selling medicines in Pennsylvania. Lorenzo Da Ponte died on August 17, 1838, in humiliating poverty, a few blocks away from the boarded-up building of his theater. His grave in one of the New York cemeteries, which was not marked, eventually got lost. Essentially, the same post-mortem fate befell his friend Mozart.
Charming Mini-EVs of Europe: A Street-Side Review in Amsterdam | September 21 2025, 17:41
I found such little cars in Europe very charming. All from Amsterdam, there are many of them there. It seems there are none in the USA, not even on college campuses. I think if they ventured onto our highways, first, everyone would crane their necks, and second, they would be blown away by the wind. Among those shown, the most interesting is the Microlino, a little green one. It has a door literally at the front. Electric. 15-18K euros. Among the rest, Opel, FIAT, and Citroen also have nice designs.
Living in the Valley of Data Centers: The NSA’s Gigantic Utah Facility | September 20 2025, 20:06
I live right in the valley of data centers, like 80% of internet traffic goes through us (a dangerous place!). I drove by one of them today, and later at home, while Googling stuff about data centers, stumbled upon the NSA’s data center in Bluffdale, Utah.
It serves as a data repository for the U.S. intelligence community. Capacity — something like 5 trillion terabytes. 5,000,000,000,000,000 gigabytes. Back in 2013, it was 100-1000 times less, but 12 years have passed, Moore’s Law and all that. Hard drives in data centers usually have a lifespan of 3-5 years. Meaning, since the launch of the data center, they have all been replaced several times with obviously greater capacity.
It is expected that the data center will be able to process “all types of communications, including the full content of private emails, mobile phone conversations, internet browsing, as well as all types of personal data: parking receipts, travel itineraries, purchases in bookstores, and data of other transactions made using digital technologies.”
The amount of data this facility is able to store is, of course, classified, but estimates “several yottabytes”. Yottabyte = 1000 zettabytes = 1,000,000 exabytes = 1 trillion terabytes. To store all the books ever written in any language would require just 400 terabytes.
In 2013 it consumed no less than 65 MW with a potential of 100 MW. Water — ~1.5–1.7 million gallons (5.7–6.4 million liters) per day for cooling servers. The water is treated with chemicals (to prevent corrosion) and discharged, leading to criticism in arid Utah — especially amid the record heat from 2022–2025 and the shortage of fresh water. There’s no closed-loop system, and it remains a “hot” topic in local discussions.
The Maunder Minimum’s Impact on Stradivari’s Unique Violins | September 18 2025, 21:20
I stumbled upon an interesting scientific hypothesis from 2003 regarding why Stradivari violins (and those of his contemporaries) are so unique. Traditional hypotheses—about the secrets of the varnish or the aging of the wood—prove insufficient. According to this hypothesis, the entire blame lies with the Maunder Minimum, a period of reduced solar activity occurring from 1645–1715, during which the tree growth rate slowed down due to the climate, meaning the wood was denser. The hypothesis suggests that amidst the perfect combination of altitude, humidity, and temperature, this environmental shift provided material with unique properties, ideal for resonant soundboards.
Stradivari was born a year before the Maunder Minimum began. His “Amati Period” (1666–1690), “Experimentation Period” (1690–1700), and “Golden Period” (1700–1720), during which he perfected and produced his best instruments (see Henley 1961), all coincided with the Maunder Minimum. Cremona’s craftsmen during this period used the only wood available to them, i.e., from trees growing during the Maunder Minimum. Neither before nor after this period was such wood available. And, probably, it is nowhere to be found in the world even now.
But really, modern violins are also quite something. Two-three hundred years ago, musicians extracted the maximum from an instrument through trial and error, whereas now it is done through meticulous calculation of sound. It is almost impossible to differentiate violins by their sound anymore, and the difference lies in the realm of individual preferences, rather than an undisputed objective worse-better.
Hi, I'm Rauf Aliev. 