No publisher. No university. No company. One person, working in his spare time, without ads or a paywall. That is the setup behind one of the most quietly impressive educational projects on the internet — and it recently shot to the top of Chinese social media, where a Zhihu post praising it collected over 1,600 upvotes and 3,600 saves in days.
His name is Bartosz Ciechanowski. He used to be an iOS engineer. On weekends, instead of gaming or scrolling, he writes physics, math, and engineering articles that you do not read so much as operate.
Open his article about mechanical watches, and you can drag the watch to spin it around, pull a slider to peel the case away, hand-wind the crown yourself, and slow down time to watch the escapement tick, click, and release. Every one of these demos is real-time 3D running inside the browser. There is not a single video.

Thousands of Words, Dozens of Hand-Written Visualizations
His catalog reads like a physics syllabus with the boring parts removed: the Moon and ocean tides, GPS satellites, internal combustion engines, how a bicycle stays upright. Each article runs to several thousand words with dozens of hand-coded interactive diagrams.
The Moon piece, for example, drops you into a cosmic sandbox where you can drag planets, tweak velocities, and watch gravity bend their paths. The GPS article renders orbiting satellites and lets you explore the timing physics that makes positioning work. The bicycle article literally balances itself on your screen as you steer it.
All of it is written, modeled, and programmed by one person — with the polish of a small studio's product and the focus of a single obsessive mind.

"Better Than a University That Charges You Tens of Thousands of Dollars a Year"
The Zhihu post that went viral is blunt about the contrast. A quoted comment from the author of the similarly excellent site ciechanow.ski (Bartosz himself) puts it directly: the quality is better than universities that charge tens of thousands of dollars a year.
The comment section adds a layer of context that feels increasingly rare. One reader joked that the site cannot possibly be AI-generated — it does not even break chapters
