Strata

Band heights from a Dirichlet draw, colours walking a palette.

images.strata · v1 · renderer canvas

22 bands · Dir(α = 0.85) · thickest 14.8% of the height · 0 thinner than a pixel

Heights are one draw from a symmetric Dirichlet with α = 0.85, built the standard way: one Gamma(α, 1) per band, normalised by their sum. Every boundary is then displaced by its own fractal noise and its own tilt, so bands pinch out and reappear rather than running parallel — and where two boundaries would cross, the lower one is clamped to the upper and the band between them simply runs out, which is what a real stratum does.

[data-canvas-stage] { display: none; }

Drawn in the browser

This generator does not send you an image. The server sends a short description of one — the parameters below, plus a 32-byte key — and the drawing is done here, from the same byte stream the server would have used. That needs JavaScript, so with it switched off there is nothing to show.

The description itself is still public: /api/v1/g/images.strata returns it, and the maths is in resources/js.

22 bands · Dir(α = 0.85) · thickest 14.8% of the height · 0 thinner than a pixel

Controls · from schema()

Width

256 2048

Height

256 2048

Bands

2 70

Dirichlet α

0.15 6

Below 1, a few bands take almost everything and the rest are hairlines. At 1 the heights are as unstructured as heights can be. Above 3 they all converge on the same thickness, which is a colour chart rather than a cliff.

Boundary wander

0 0.3

How far a boundary strays from its nominal height, as a fraction of the canvas. Zero draws a bar chart; this is the single control that makes it rock.

Wander scale

0.3 12

How many undulations fit across the canvas.

Boundary detail

1 7

Octaves in the noise displacing each boundary. One is a smooth wave; more adds the fine crumbling of a real edge.

Tilt

0 0.35

A linear slope added to each boundary, drawn independently per band — so the stack shears the way tilted bedding does.

Within-band shading

-0.25 0.25

How far along the palette a band travels between its own top and bottom. Flat fills read as coloured strips; a gradient reads as a surface with light on it.

Colour step

0.01 0.5

How far the colour moves between one band and the next. Small steps keep neighbouring layers related, which is what makes the stack read as one formation.

Ground

Colour

Palette size

2 12

Grain

0 0.1

Film grain over the finished render. Strata want more of it than most things here — flat coloured areas are exactly where 8-bit output shows its seams.

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 NIST Randomness Beacon.

seed token MTTKJD9R22CNQSW9TBZV49MQAM

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

Burned into the corner before the file is written, so the image keeps its provenance wherever it ends up:

entropy in

16 bytes

stream used

1,124 bytes

rejections

duration

507 µs

palette

background

#010103

bands

concentration

0.85

thickest share

14.8% (even would be 4.5%)

Seed receipt

Class B · Public beacon cached

NIST Beacon pulse #1,941,315 — chained to every pulse before it, and signed.

Published openly — anyone can look this value up after the fact.

source: NIST Randomness Beacon
observed: 2026-09-14T17:21:00+00:00
latency: 0ms
mixed with: csprng — always

https://beacon.nist.gov/beacon/2.0/chain/2/pulse/1941315 ↗

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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.

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

Strata

Result

Measurements

Seed receipt

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