# One Black Cell

> A one-row universe to play with: every row, each cell looks at itself and its two neighbours, and one of eight small laws (the bits of a rule number from 0 to 255) says whether it is black below. Start from one black cell or a name spelled in five-bit letters, take the rule from a number, a birthday or the eight law cards, and the page sews 64 rows into a patchwork quilt. One metered run reads your wish and names the single law to flip.

URL: https://one-black-cell.skillsafe.ai/
API: https://one-black-cell.skillsafe.ai/api.html
Built on: @anthropics/algorithmic-art (https://skillsafe.ai/skill/@anthropics/algorithmic-art) - state what a simple seeded process does and explore it one parameter at a time.

## Free, in the browser

- The universe: 64 rows on a strip wide enough to act as an endless row; the cells beyond the strip follow the rule on an all-white (or all-black) background.
- The page's estimate of the behaviour, checked in order: fades (every row goes flat), lives on the edge (one of the six documented complex rules: 54, 110 and their mirror and colour-swapped twins), nests (from one black cell, the pattern pinches back to a few cells at rows 8, 16 and 32), repeats (rows 40 to 63 repeat with a period of up to 12 rows, still or sliding), otherwise churns. An estimate from 64 rows, not a proof.
- Facts: density inside the growing pattern, how fast each side spreads, the widest white gap with black on both sides, the centre column for rows 0-31, the mirror and colour-swapped twin rules, and a documented resemblance for a few rules.
- The eight one-law flips: the rule, behaviour and density you get by flipping each law on its own.
- A free check: pick one of the five behaviours and the page says whether this universe is already there, one flip away (naming the closest flip, with a button to try it) or no single flip away. After any flip, "Back to rule N" swaps back for a before/after look.
- A birthday rule is the day of the year (non-leap count), wrapped past 255. A name is spelled A = 00001 ... Z = 11010, up to 12 letters.
- Exports: Markdown, the 0/1 grid as CSV, JSON, and the quilt as SVG or PNG.

## The one paid task: reading

Input (all strings): task "reading", rule, seed, wish, page_facts (the facts above and the eight flips, one "key | ..." per line).
Reply (one JSON object): title, wish_target (fades, repeats, nests, churns or edge - read from the wish alone), verdict (already, one_flip or no_flip), verdict_reason, pick_flip (a law such as WBB, or empty), flip_note, philosophy (a 40-80 word field guide), look_for (two or three {fact, text} items).
Verdict rule, in order: already when the page's estimate equals the wish target; one_flip when one of the eight flips shows it (the flip closest in density is named); otherwise no_flip.
The page re-checks every reply: the verdict against the rule, the named flip, the facts each item points to, every number in the prose, and the word limits.

## Why it is fun

Rule 30 grows a whole universe from a single black cell; this page lets you play with all 256 rules in its family and see what one law changes.