Cards

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A researcher in a rubber mask mobbed by crows on a campus for seventeen years, where birds hatched long after the original trapping had learned the face from birds that were never caught either

Animal MindsSep 22, 2026

The Face Seven Crows Never Forgot

animal-minds crows memory

Envelope encryption splitting one key into many short-lived data keys wrapped by a master key inside a hardware module, with every unwrap logged and rotation touching the small keys rather than every row

SecurityDay 51Sep 22, 2026

The Key That Guards The Keys

system-design security encryption

Vasili Arkhipov beside the Soviet submarine B-59 trapped beneath the Caribbean in October 1962, where a nuclear torpedo needed three signatures and he refused to give the third

HistorySep 21, 2026

The Man Who Wouldn't Sign

history peace cold-war

A user fired at 10am whose JWT stays valid until 11, the three parts of a self-contained token, and short-lived access tokens paired with a server-side refresh token that can actually be invalidated

SecurityDay 50Sep 21, 2026

The Token We Can't Take Back

system-design security jwt

An eleven-bed eye clinic in Madurai growing into a cross-subsidised system where half the patients pay nothing, over 700,000 surgeries a year, and infection rates below the international norm

Social InnovationSep 20, 2026

How Sight Became Affordable

social-innovation healthcare tamil-nadu

Handing an app a password against granting it a scoped token, the five steps by which the app never sees the credential, and what OpenID Connect adds on top of OAuth

SecurityDay 49Sep 20, 2026

Let Them In Without Giving Them the Keys

system-design security oauth

Authentication answering who you are against authorization answering what you may do, the one-digit URL change that reaches another person's record, and enforcing ownership at the data layer

SecurityDay 48Sep 19, 2026

Logged In Is Not the Same as Allowed

system-design security authorization

The Michelangelo effect in close relationships, where a partner who sees and reflects the person you are becoming measurably moves you toward it, and both people grow

PsychologySep 19, 2026

The Figure Was Already in the Marble

psychology relationships michelangelo-effect

The same architecture diagram seen from the builder's view and the attacker's view, the six STRIDE prompts applied to every arrow, and trust boundaries as the place to ask

SecurityDay 47Sep 18, 2026

Draw the System, Then Draw the Attacker

system-design security threat-modelling

A language model's training data printed to a stack taller than the International Space Station against the twenty metres a twelve-year-old has heard, and the unexplained data efficiency gap between them

The Most Efficient Learner Ever Built

ai language-models child-development

A 2TB table moving onto four shards with no downtime through dual write, backfill, verify, gradual read shift and finish, set against the naive stop-and-copy plan

DatabasesDay 46Sep 17, 2026

Splitting a Table While People Are Using It

system-design databases sharding

A 2009 study finding French newborns cry with a rising melody and German newborns with a falling one, matching the intonation heard through the womb wall in the last trimester

Child DevelopmentSep 17, 2026

The Babies Who Cry With an Accent

child-development language infants

A column rename breaking during a rolling deploy while both code versions are live, and the expand-migrate-contract sequence that makes each step safe alone and reversible

DatabasesDay 45Sep 16, 2026

Never Change Anything in One Step

system-design databases migrations

The 1942 phantom bottom found by sonar, revealed as a dense layer of lanternfish, krill and squid, and the daily vertical migration that is the largest movement of life on Earth

OceanographySep 16, 2026

The Seafloor That Rose at Sunset

oceanography marine-biology sonar

B-tree, GIN, BRIN, partial and covering indexes compared by the question each one answers, and a billion-row table where BRIN costs 300 KB against a B-tree's 5 GB

DatabasesDay 44Sep 15, 2026

Not Every Index Is a Tree

system-design databases indexes

October 1582 losing ten days to the Gregorian correction, the eleven-minute Julian drift behind it, Britain holding out until 1752, and Sweden inventing February 30th

TimeSep 15, 2026

The Ten Days That Never Happened

history calendars time

Why every Postgres connection is a separate OS process costing megabytes, how 500 connections on 16 cores collapses throughput, where the queue forms under a small pool versus a large one, and a pooler as the fix

DatabasesDay 43Sep 14, 2026

A Connection Costs More Than You Think

system-design databases connection-pooling

Paddy from a burial urn at Sivagalai dated to 1155 BCE, Keeladi as a nine-phase planned industrial town, and the other Tamil sites carrying the same story

ArchaeologySep 14, 2026

The Grain That Dated a Civilisation

archaeology tamil-nadu keeladi

Axelrod's 1980 Iterated Prisoner's Dilemma tournament, Rapoport's four-line Tit for Tat and its four traits, its second win against 62 entries, and the caveat that the result was setting-dependent

Game TheorySep 13, 2026

Four Lines Beat Everyone

game-theory tit-for-tat axelrod

The viral 'hated by fools' line attributed in turn to Cocteau, the Buddha and Kalam with no source behind any of them, beside what Cocteau actually wrote and Emerson on being misunderstood

On Being DislikedSep 12, 2026

Read The Bill

on-being-disliked quotes cocteau

Index lookup against sequential scan for the same query, the row-count threshold where the planner switches, three ways statistics mislead it, and ANALYZE before reaching for a new index

DatabasesDay 42Sep 12, 2026

Why It Ignored Your Index

system-design databases query-planner

What was rebuilt after September 11, 2001 — the skyline, the markets, aviation protocol, institutions, trust — set against the 2,977 names read aloud each year, the one loss that stays

On What LastsSep 11, 2026

Everything Except One Thing

on-what-lasts september-11 memory

The write-ahead log ordering — transaction, append to WAL, fsync, modify in memory, flush data pages later — with crash recovery replaying committed changes, and the same log driving replication, PITR and audit

DatabasesDay 41Sep 10, 2026

Write It Down Before You Do It

system-design databases write-ahead-log

Concorde's per-flight economics — $100,000 revenue against $200,000 operating cost — and the sunk cost fallacy named after it, read as grief avoidance rather than bad arithmetic

EconomicsSep 9, 2026

The Plane The Fallacy Is Named After

economics sunk-cost-fallacy concorde