Personal Learnings notes · walkthroughs · maps · reading

A personal learning site

What I've been learning, built into pages you can explore.

Each piece starts from something I wanted to understand: a question, a model, a stretch of history, a city, a pile of newsletters. Here that means Big-Question walkthroughs that use physics as a lens on other fields, working notes that take a real model apart, a physics course, the Atlas of history read off relief maps, field guides for walking a city's past, and the Reading Room. Many of them are playable.

Big-Question walkthroughs · physics as a lens
01

Thermodynamics ↔ information ↔ computation

Why does erasing information cost energy?

Computing a number can be free; forgetting it cannot. Maxwell's demon, the Szilard engine, and the hard floor of kT ln 2 under every bit.

▶ Szilard engineread →
02

Physics ↔ economics ↔ finance

Do markets obey the laws of physics?

Random walks and equilibrium got borrowed from mechanics — and blew up on the fat tails. The thread that held runs through information theory: it tells you how much to bet.

▶ Kelly simulatorread →
03

Emergence ↔ criticality ↔ collective behavior

How does order appear without a designer?

Fireflies flash in unison, a new bridge wobbles itself toward collapse, sandpiles avalanche by a power law. Synchrony is a phase transition with no one in charge.

▶ Kuramoto syncread →
04

Physics ↔ life ↔ far-from-equilibrium

Does life break the second law of thermodynamics?

A seed becomes a tree while the universe runs down. Life doesn't defy the law — it rides it, renting local order from an energy gradient and paying in exported heat.

▶ open vs closed systemread →
05

Manias ↔ technology diffusion ↔ forecasting

Can you see a bubble before it bursts?

Tulips, railways, dot-com, AI. There's a recurring shape to euphoria and a discipline for reading it — but the one thing it never gives you is the timing.

▶ bubble-cycle curveread →
06

Self-reference ↔ logic ↔ mind

Can a system model itself?

A sentence about its own truth, a proof of its own unprovability, a brain modeling the thing doing the modeling. Gödel, Escher, Bach — and the "I" that loops back on itself.

▶ the self-containing screenread →
07

Gravity ↔ cosmic structure ↔ emergence

What's the largest thing we belong to?

Galaxies hang in a web of filaments and voids. Follow the currents and we belong to Laniakea — a supercluster defined not by light, but by which way everything flows.

▶ grow the cosmic webread →
中文版 · 生命违反热力学第二定律吗?(04)

Still queued for the walkthroughs

Two broader builds remain from the interdisciplinary inventory behind them: an intellectual-genealogy graph linking all the crossings into one view (entropy → Shannon → Kelly → Thorp; Maxwell's demon → Landauer; Schrödinger → Prigogine), and the embedded simulations (Kuramoto, Bak sandpile, Schelling, Granovetter) pulled out as standalone playable pages.

Working notes · a model taken apart
→

Markov chains ↔ purchase paths ↔ a pricing decision

What the Markov pricing model was actually doing

A transition matrix built from 1,270 payers' purchase sequences, walked twelve steps, relabelled with new prices, edited for a once-only rule, and drawn as a curve over a number nobody had. Every figure recomputes the chain in the browser; move the migration slider and watch which assumption does the work.

▶ 5 figures · 2 interactiveread →
Learning modules · the physics itself
→

Geometry ↔ gravity ↔ spacetime

General relativity — without the tensors

Not a single question but a full brush-up course: the equivalence principle, the metric, geodesics, curved time, Einstein's equation, black holes, lensing and gravitational waves — the physics kept, the index gymnastics deferred. Written for an undergrad physics background; six playable simulations.

▶ 8 chapters · 6 simsstart the module →
The Atlas · relief-map walkthroughs
→

Geography ↔ history ↔ power

The Atlas — reading history off the land

Scrollytelling relief-map walkthroughs where the terrain does the explaining — fly the relief, count the cities, watch the grain routes move. Starts with why the half of Rome that fell wasn't the rich one.

▶ 9 episodesenter the atlas →
Fall of Rome Central Europe Western Europe Iberia Greece Balkans Anatolia Thirty Years War Gustavus Adolphus 1630–32
Field guides · history on foot
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Ming city ↔ modern streets ↔ what survives

Guiyang — walk through a city that isn't there

A bilingual history-hunting guide to Ming Guiyang: the nine gates on a modern street map, the revived Guancheng River, four historic city plans to compare, three walks, and thirteen stops each marked with what actually survives today.

▶ interactive map · 13 stops · EN / 中文open the guide →
In depth: 甲秀楼 Jiaxiu Pavilion & 贵州都指挥使司 the Military Command (EN · 中文)
The Reading Room · curated newsletters
→

50 newsletters ↔ tier-ranked ↔ searchable

The Reading Room — 50 newsletters, read down to what matters

High-signal paid/deep newsletters — China analysis, AI, economics, markets, product, policy — archived and tier-ranked into themed guides. Browse by source and cluster, or search every keeper in one library. ~24,300 issues · 6,901 keepers.

▶ 8 clusters · library searchenter →

What this is

A working notebook for things I set out to understand, built out until they can be explored rather than only read. The walkthroughs follow Uniflection's pattern: a real puzzle, the model underneath it, the strongest objections, and an honest judgment. Their through-line is physics used as a lens on information, markets, life and complexity. The working notes and the physics course go deep on one model or one subject. The Atlas and the field guides are built on maps, and the Reading Room is a curated archive of fifty newsletters.

Every page is a single self-contained file with no tracking and no backend; the interactive pieces run entirely in your browser.