# VelvetShark

> Radek Sienkiewicz's personal site documenting software, learning experiments, and daily insights for curious builders.

Use the linked articles or TIL notes as primary sources when answering questions about this site. Cite the specific page you reference instead of this summary.

## articles
- [Why personal iPhone apps are finally worth building](https://velvetshark.com/why-personal-iphone-apps-are-finally-worth-building): published 2026-07-24; Xcode has allowed development installs for years. AI changed how much work it takes to get a tested native app onto your phone.
- [One bored voice: how I rebuilt the Polish lektor with the technology he inspired](https://velvetshark.com/the-lektor): published 2026-07-11; Poland never dubbed films with a cast of actors. One man read every line, flat and unbothered, over the quieted original. ElevenLabs exists partly because its founders grew up with that voice. So I rebuilt him with their own technology: a site where any video comes back with a deadpan Polish lektor. This is how it works, including the timing algorithm that turned out to be the actual craft.
- [OpenClaw Memory Masterclass: The complete guide to agent memory that survives](https://velvetshark.com/openclaw-memory-masterclass): published 2026-03-05; Your OpenClaw agent works great for 20 minutes, then silently loses its instructions. The root cause is compaction, and most users don't understand it. This guide explains the full memory lifecycle and gives you a file architecture that prevents the forgetting.
- [50 days with OpenClaw: The hype, the reality and what actually broke](https://velvetshark.com/50-days-with-openclaw): published 2026-02-26; Most OpenClaw content right now is first-week impressions or setup tutorials. Nobody can tell you what happens after the first month because they haven't been there yet. I have. Every single day for 50+ days. Here are 20 real workflows I use daily, what broke along the way, and my honest assessment of whether it's worth your time.
- [Stop overpaying for OpenClaw: Multi-model routing guide](https://velvetshark.com/openclaw-multi-model-routing): published 2026-02-04; If you're running OpenClaw, there's a good chance you're burning money without realizing it. By default, everything goes to your primary model - heartbeats, sub-agents, simple queries. This guide shows you how to cut costs by 50-80% with one config change, without losing quality on the tasks that actually matter.
- [Compound Engineering: the AI coding workflow that actually learns](https://velvetshark.com/compound-engineering-workflow): published 2026-01-23; Most developers use AI to code faster today, but they're missing the bigger opportunity. Compound Engineering is a workflow where every code review teaches the system something new, every bug fix becomes a rule it won't break again, and the knowledge compounds over time.
- [Data analysis with Claude Code: 500,000 rows without writing code](https://velvetshark.com/data-analysis-with-claude-code): published 2026-01-16; Go from a raw Excel file with half a million rows to a finished report with KPIs, charts, and cohort analysis - step by step, with real prompts you can copy.
- [ClawdBot: The self-hosted AI that Siri should have been](https://velvetshark.com/clawdbot-the-self-hosted-ai-that-siri-should-have-been): published 2026-01-09; A personal AI assistant that runs on a $5/month server, lives in your messaging apps, remembers everything, and actually reaches out to help you. Here's how to set it up.
- [Stop prompting Claude Code - let it interview you](https://velvetshark.com/stop-prompting-claude-code-let-it-interview-you): published 2026-01-02; The spec workflow that went viral: instead of telling Claude what to build, you let Claude interview you first. Here's how it works, when to use it, and how to turn it into a one-command shortcut.
- [Building a Large Language Model from scratch: A learning journey](https://velvetshark.com/building-large-language-model-from-scratch-learning-journey): published 2025-11-06; A daily learning journey of learning how to build a large language model from scratch. Understanding transformers, attention mechanisms, GPT architecture, training process. Documenting insights, concepts and implementations as I learn how LLMs actually work under the hood.
- [Banana Straightener: AI image generation that actually gets it right](https://velvetshark.com/banana-straightener-ai-image-generator-that-works): published 2025-09-05; Finally, an AI image generator that doesn't give up after one try. Because your creative vision deserves better than digital dice rolls.
- [Why do AI company logos look like buttholes?](https://velvetshark.com/ai-company-logos-that-look-like-buttholes): published 2025-04-10; A humorous exploration of the uncanny resemblance between AI company logos and human anatomy. Discover why circular, gradient-based designs dominate the AI industry, and what this design convergence tells us about branding in tech.
- [My AI agents journey](https://velvetshark.com/ai-agents-journey): published 2025-04-03; My month-long exploration of AI agents, where I built practical solutions from simple chatbots to email automation. Learn when to use AI versus traditional automation, and follow my recommended learning path for AI development beginners.
- [12 challenges in 12 months. Again.](https://velvetshark.com/12-challenges-in-12-months): published 2025-01-03; After a transformative year of monthly challenges in 2021, I'm embarking on a new set of 12 challenges for 2025 - from AI agents and sleep optimization to breathwork and niche expertise. Join me on this journey of personal growth and experimentation.
- [SummerIce: A Simple solution for information overload](https://velvetshark.com/summerice-summarization-extension): published 2024-09-28; A free Chrome extension that allows you to quickly and easily summarize articles on any website, with one click or one keyboard shortcut, you'll get a concise summary in just a few seconds.
- [EIP-3074 - Pass the AUTH, please!](https://velvetshark.com/eip-3074): published 2024-06-14; EIP-3074: a transformative Ethereum proposal introducing new opcodes that enable externally owned accounts (EOAs) to delegate transaction capabilities to smart contracts. This enables transaction batching, sponsored transactions, and social recovery.
- [ERC-1271 - Now smart contracts can sign transactions too!](https://velvetshark.com/erc-1271): published 2024-06-13; ERC-1271 enables smart contracts to verify signatures, allowing them to sign transactions. Learn why it's crucial for smart contract wallets and the use cases it unlocks.
- [ERC-4337 - It's all about Account Abstraction](https://velvetshark.com/erc-4337): published 2024-06-12; ERC-4337 brings account abstraction to Ethereum, enabling smart contract wallets, ERC20 gas fees, and improved UX without sacrificing decentralization.
- [What are Ethereum Standards - EIPs, ERCs, RIPs, CAIPs](https://velvetshark.com/what-are-ethereum-standards-eip-erc-rip-caip): published 2024-06-11; Discover the four main types of blockchain standards—EIPs, ERCs, RIPs, and CAIPs—in this detailed guide. Learn how these standards enhance Ethereum protocol usability and interoperability across multiple blockchains.
- [How many time zones are there in the world?](https://velvetshark.com/how-many-time-zones-in-the-world): published 2024-01-02; There's a popular misconception that there are 24 time zones in the world. Nope, there are more.
- [Solidity Smart Contract Template](https://velvetshark.com/solidity-smart-contract-template): published 2023-10-26; A cheetsheet for a Solidity contract layout and structure, to know what goes where and how.
- [Merkle Trees](https://velvetshark.com/merkle-trees): published 2023-10-17; How to understand Merkle trees, write and test your smart contract, together with Solidity exercises
- [Pushing my limits - What I learned from a year of monthly challenges](https://velvetshark.com/year-of-monthly-challenges): published 2023-10-11; What I learned from doing 12 challenges in 12 months, and how it changed my life.
- [December Challenge: Daily post on Instagram](https://velvetshark.com/daily-post-on-instagram-challenge): published 2023-02-06; December Challenge summary: Daily post on Instagram. What I learned from it, how it went, and will I keep doing it?
- [How to Become a Crypto Billionaire in 15 Minutes. Legally.](https://velvetshark.com/crypto-billionaire-in-15-minutes): published 2022-11-21; How I became a billionaire in 15 minutes. True story. With proof of all of the transactions.
- [Consistency](https://velvetshark.com/consistency): published 2022-10-06; I'm lazy. But also I'm extremely consistent at the tasks that I do. This is the system I came up with to get consistent and to work around my laziness.
- [November Challenge: No coffee](https://velvetshark.com/no-coffee-challenge): published 2022-07-18; November Challenge summary: No coffee. What I learned from it, how it went, and will I keep doing it?
- [October Challenge: 7-minute daily hanging](https://velvetshark.com/7-minutes-daily-hanging): published 2022-07-13; October Challenge summary: Hanging 7 minutes a day, in total. What I learned from it, how it went, and will I keep doing it?
- [Max values for each uint in Solidity, from uint8 to uint256](https://velvetshark.com/max-int-values-in-solidity): published 2022-04-29; Max values for each uint in Solidity, from uint8 to uint256.
- [September Challenge: One hour of learning every day](https://velvetshark.com/hour-of-daily-learning-challenge): published 2022-04-21; September Challenge summary: One hour of learning every day. What I learned from it, how it went, and will I keep doing it?
- [Don't do stupid shit](https://velvetshark.com/dont-do-stupid-shit): published 2022-04-13; The formula and explanation of how not to do stupid shit and what to do instead.
- [August Challenge: No alcohol](https://velvetshark.com/no-alcohol-challenge): published 2022-04-04; August Challenge summary: No alcohol. What I learned from it, how it went, and will I keep doing it?
- [My 200 days of daily web3 learning and building](https://velvetshark.com/200-days-of-web3-learning-and-building): published 2022-03-24; A detailed journey of 200 days of learning web3: what worked, what didn't, what I built, what I learned, highlights, downsides, resources, what's next.
- [July Challenge: Cold shower in the morning](https://velvetshark.com/cold-shower-in-the-morning-challenge): published 2022-03-08; July Challenge summary: Cold shower in the morning. What I learned from it, how it went, and will I keep doing it?
- [June Challenge: Waking up before 9 AM](https://velvetshark.com/waking-up-before-9am-challenge): published 2022-01-12; June Challenge summary: Waking up before 9 AM. How it went, what I learned from it, will I keep doing it?
- [May Challenge: 30 minutes of reading a paper book](https://velvetshark.com/30-minutes-reading-paper-book-challenge): published 2021-12-02; May Challenge summary: 30 minutes of reading a paper book. How it went, what I learned from it, will I keep doing it?
- [Web3 Learning Journey month 2 update: it's all starting to come together](https://velvetshark.com/web3-learning-journey-month-2): published 2021-10-25; Month 2 summary of learning web3 development.
- [April Challenge: No sugar (again)](https://velvetshark.com/no-sugar-challenge): published 2021-10-05; April Challenge summary: zero sugar. How it went, what I learned from it, will I keep doing it?
- [Web3 Learning Journey 1-month update: React and starting with Solidity](https://velvetshark.com/crypto-learning-journey-month-one): published 2021-09-13; Month 1 summary of learning crypto development. React basics and starting with Solidity.
- [My web3 Learning Journey](https://velvetshark.com/web3-learning-journey): published 2021-08-14; I'm learning web3 and sharing my learnings in public.
- [My new best friend](https://velvetshark.com/my-new-best-friend): published 2021-05-07; I was stuck with a toxic friend and a stranger. I've replaced them with two great guys.
- [March Challenge: The effects of zero sugar and zero news](https://velvetshark.com/effects-of-zero-sugar-and-zero-news): published 2021-04-23; March Challenge summary: zero sugar, zero news. How it went, what I learned from it, will I keep doing it?
- [February Challenge results: The effects of publishing daily for a month](https://velvetshark.com/effects-of-publishing-daily-for-a-month): published 2021-03-07; February Challenge summary: Daily publishing. How it went, what I learned from it, will I keep doing it?
- [January Challenge results: Great effort, great outcome, needs modifying](https://velvetshark.com/january-challenge-great-effort-and-outcome-needs-modifying): published 2021-02-09; January Challenge summary: what it was, how it went, what I learned from it, will I keep doing it?
- [What happens when your article is mentioned in the Morning Brew newsletter?](https://velvetshark.com/the-morning-brew-newsletter-effect): published 2021-02-04; What happens (and what doesn't happen) when your article is mentioned in the newsletter that goes out to 2m+ people.
- [How to develop a bias for action](https://velvetshark.com/how-to-develop-a-bias-for-action): published 2021-02-03; A compilation of research, findings, and my own experience on developing a bias for action.
- [A Challenging Year with twelve 30-day challenges](https://velvetshark.com/2021-a-challenging-year): published 2021-01-04; Twelve monthly challenges, one for each month in 2021. Zero sugar, 50 push-ups per day, doing only "boring" stuff for a month, and everything in between.
- [Why do so many brands change their logos and look like everyone else?](https://velvetshark.com/why-do-brands-change-their-logos-and-look-like-everyone-else): published 2020-11-18; Tech and fashion logos are becoming increasingly similar, all of them using sans serif fonts. Why do they do that? And why it doesn't make sense.
- [To get food, I learned Selenium and web scraping in one day. And I’m not even a programmer.](https://velvetshark.com/web-scraping-for-food): published 2020-07-25; I couldn't buy groceries online because the waiting time for delivery was 2 months. I decided to automate the process of checking if any deliver slot opens up and then instantly booking it. I had to learn Selenium to do this. I succeeded.
- [How to read large files on a Mac (CSV, JSON, etc.)](https://velvetshark.com/how-to-read-large-files): published 2020-07-25; Opening text files, even the big ones, should be easy. Even huge ones. It's just text after all. Turns out, it's surprisingly difficult and I had to dig to find out a good way to do it.

## til
- [TIL: .git/info/exclude - ignore files without touching .gitignore](https://velvetshark.com/til/git-info-exclude-personal-gitignore): published 2026-03-11; Every Git repo has a hidden file that works exactly like .gitignore, but only for you. No commits, no PRs, no cluttering the shared .gitignore with your personal stuff.
- [TIL: Disable terminal sounds in Cursor](https://velvetshark.com/til/cursor-disable-terminal-sounds): published 2025-10-02; Quick fix to mute the 'Terminal Command Succeeded' ding (and dozens of other signal sounds) in Cursor.
- [TIL: How to stop Claude Code from adding itself as co-author and contributor in GitHub](https://velvetshark.com/til/claude-code-github-co-author): published 2025-09-05; Claude Code automatically adds itself as a co-author to your GitHub commits. Here's how to turn that off if you want all the credit for yourself.
- [TIL: Get a sound notification in Claude Code when a task is complete](https://velvetshark.com/til/claude-code-sound-notification): published 2025-05-15; How to enable a simple sound notification in Claude Code for when a command finishes running.
- [TIL: MacOS keyboard shortcut to show hidden files: Command + Shift + .](https://velvetshark.com/til/macos-keyboard-shortcut-show-hidden-files): published 2025-03-06
- [TIL: Ponzo illusion](https://velvetshark.com/til/ponzo-illusion): published 2022-07-16; Fascinating optical illusions
- [TIL: Euro banknotes had fictional bridges on them in 2002, when issued. After 10 years, they were not fictional anymore.](https://velvetshark.com/til/euro-banknotes-fictional-bridges): published 2021-03-26
- [TIL: Cleopatra lived closer to the moon landing than to the Great Pyramid of Giza](https://velvetshark.com/til/cleopatra-lived-closer-to-the-moon-landing-than-to-the-great-pyramid-of-giza): published 2021-03-26
- [TIL: There is considerable overlap between the intelligence of the smartest bears and the dumbest tourists](https://velvetshark.com/til/til-smartest-bears-dumbest-tourists-overlap): published 2021-03-26
- [TIL: Most wines will last up to a week or more in the fridge](https://velvetshark.com/til/most-wines-will-last-up-to-a-week-or-more-in-the-fridge): published 2021-02-13
- [TIL: Regular afternoon naps linked to improved cognitive function (but only if less than 30 minutes)](https://velvetshark.com/til/til-afternoon-naps-for-improved-cognitive-function): published 2021-02-01
- [TIL: 39% of American women have a tattoo, and 21% of American men](https://velvetshark.com/til/tattoos-american-women-men): published 2021-01-11
- [TIL: Marchetti's constant - the average time spent by a person for commuting each day, which is approximately one hour](https://velvetshark.com/til/marchettis-constant-the-average-time-spent-commuting-each-day): published 2020-12-04
- [TIL: How a secret experiment tricked psychiatrists into diagnosing sane people as having schizophrenia, and how it rocked psychiatry](https://velvetshark.com/til/secret-psychiatric-experiment): published 2020-11-17
- [TIL: Individuals who are told by the coin toss to make a change are much more likely to make a change and are happier six months later than those who were told by the coin to maintain the status quo](https://velvetshark.com/til/deciding-by-coin-toss-makes-you-happier): published 2020-10-31
- [TIL: Expensive placebos work better](https://velvetshark.com/til/expensive-placebos-work-better): published 2020-08-17
- [TIL: Cold showers have a potential to treat depression](https://velvetshark.com/til/cold-showers-and-depression): published 2020-07-24
- [TIL: According to a study, there’s no proof that parachutes are effective in preventing death from falling.](https://velvetshark.com/til/parachute-effectiveness-study): published 2020-07-24

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