# Bookmarks

Things I love on the internet, and the bugs that taught me (and the industry) the most.

Worth your time

The Evolution of Trust - Nicky Case's playable explainer on game theory and why we cooperate. The bar for 'article as a game'.
ciechanow.ski - Bartosz Ciechanowski's interactive explainers (gears, GPS, the mechanical watch). Hand-built, jaw-dropping.

Post-mortem Stories

War and crazy stories worth knowing.

Mariner 1 (1962) - A missing overbar in transcribed guidance math, "the most expensive hyphen in history." Test what you transcribe.
Vancouver Stock Exchange index (1982) - The index truncated instead of rounding and bled from 1000 to about 520 in under two years. The lesson did not stick: see Knight Capital below for the same money-math hubris, now at machine speed.
Ariane 5, Flight 501 (1996) - Reused guidance code converted a 64-bit float to a 16-bit int; the faster rocket overflowed it and self-destructed. About $370M gone. Reused code outside its validated envelope.
Mars Climate Orbiter (1999) - One team used metric, the other imperial. The numbers never agreed and the orbiter burned up in the Martian atmosphere. Units are part of the contract.
Y2K (2000) and the Year 2038 problem - Two-digit years nearly broke the world at midnight 2000; 32-bit Unix time overflows on Jan 19, 2038. We keep mortgaging the future to save a few bits, and the sequel is already scheduled.
Nuclear Gandhi - Started as an apocryphal integer-underflow legend (aggression 1 minus 2 wraps around to 255). Then it became a self-fulfilling prophecy: developers loved it so much they coded the behavior into later games on purpose. A bug so good it shipped as a feature.
Knight Capital (2012) - A stale feature flag plus a partial deploy lost $440M in 45 minutes and effectively ended the firm. Deploys are production events, and once real money and floating-point math share a loop, every rounding error scales with the order book.
left-pad (2016) - An 11-line package was unpublished and builds broke across the internet. The whole ecosystem rests on tiny dependencies.
The NULL license plate (2019) - A researcher put NULL on his plate; ticket systems read it as no plate and dumped every unmatched citation on him, about $12,000 worth. Never let a magic value mean both 'nothing' and a real thing.
GTA Online load times (2021) - Seven-minute loads for years, fixed by a player: an O(n²) scan while parsing a 10MB JSON file. Profile the hot path.
The Super Mario 64 cosmic ray (2013) - A speedrunner's Mario teleported upward mid-jump with no input to explain it. The leading theory: a single ionizing particle flipped one bit in the console's RAM. Sometimes the bug is literally the universe, which is why ECC memory exists.
0.1 + 0.2 ≠ 0.3 - Floating point, in one URL. Everyone learns this twice.

ASCII Gallery

Collected ASCII art. Click any piece to view it in full; use the copy button to grab it.