Library Equations

Matrices

Any, invertible, symmetric or positive-definite — constructed, not rejection-sampled.

equations.matrix · v1 · renderer math

[1, 4, 2; -4, 5, -4; 3, 2, -6] → det = -212 — unconstrained

entropy in

16 bytes

stream used

9 bytes

rejections

duration

197 µs

problems

kind

any

Seed receipt

Class C · Observational cached

A magnitude 4.3 earthquake, 13 km NW of Cepitá, Colombia, 153.8 km down — 49 minutes ago.

Carries only tens of bits of genuine surprise. Always mixed with the OS CSPRNG.

source: USGS Seismic Feed
observed: 2026-09-13T17:55:25+00:00
latency: 0ms
mixed with: csprng — always

https://earthquake.usgs.gov/earthquakes/eventpage/us7000th7k ↗

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The token is the seed, so this link recomputes the result rather than looking it up. No database, and it works for as long as v1 does.

Controls · from schema()

Kind

Rows

2 5

Columns

2 5

Ignored by the kinds that have to be square.

Determinant

-12 12

Entries within ±

1 9

How many

1 12

Entropy source

Picking a source changes the story on the receipt, never the quality: anything below class A is mixed with the OS CSPRNG before it reaches you. This result actually came from USGS Seismic Feed.

seed token C9C8JVJ19KRY6XBVRT8KDJZ9Y8

Re-render keeps this token. Generate replaces it. That is the whole idea.

Printable worksheet 20 problems · answers on page 2

The seed is printed in the footer, so the same sheet comes back from the same link — and a different seed is a different sheet.

This page and /api/v1/g/equations.matrix run the same code. There is no private endpoint.

Matrices

Result

Measurements

Seed receipt

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