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Asterism

Author: OpenAI

Build constellations from a finite deck of named stars and illuminate the night.

Asterism app screenshot

Description

Asterism is a single-player constellation-building card game created by OpenAI with Codex and GPT-5.6. Players choose a Luminary, place named star cards into constellation diagrams, and satisfy line rules and pattern objectives without exhausting the finite deck across a three-Night run.

Build notes

Initial prompt

Build “Asterism,” a single-player constellation-building card game that is easy to understand and difficult to master. The player chooses a Luminary—Terra, Luna, or Sol—then plays a finite deck of named star cards into constellation diagrams. Every card has Light, Origin, and Spectrum. Each connecting line applies a clear scoring condition, and each completed pattern has an additional constellation objective. The core decision is which star to commit now without starving later constellations in the same Night.

Structure a run as three Nights, each with three constellations and an escalating Light target. The third constellation of each Night introduces a celestial boss that changes the puzzle rather than becoming a separate combat system. Reset the deck between Nights while preserving run-level Alignment choices. Include an Observatory where players can revisit discovered stars, constellations, Luminaries, bosses, and completed runs. Keep progression horizontal rather than adding permanent stat boosts.

Make the visual direction feel like a refined celestial folio: warm ivory, midnight blue, old gold, botanical and astronomical ornament, and tactile cards. Keep the board readable before decorative. Support mouse, touch, and keyboard play, clear accessible names, visible focus, reduced motion, and responsive desktop/mobile layouts. Add restrained animation, particles, music, and sound feedback without obscuring scoring.

Build and test the complete playable vertical slice, including tutorial, settings, local persistence, and a public Sites deployment. Run lint, build, and tests, then verify the full three-Night loop plus key responsive and accessibility states.

Iterations

  1. Explored several celestial game loops, then chose finite-deck constellation placement as the core puzzle.

  2. Built the scoring grammar: named star cards, Light, Origin, Spectrum, constellation nodes, line rules, and pattern objectives.

  3. Added Luminary selection and distinct Terra, Luna, and Sol Aspects to create different strategic openings.

  4. Expanded the prototype into a three-Night run with three constellations per Night, escalating targets, and boss disruptions on the final pattern.

  5. Added Alignments, discoveries, the Observatory, saved progress, and run history while keeping progression horizontal.

  6. Developed the celestial-folio art direction, card visual language, constellation map, portraits, and title artwork.

  7. Added motion, particles, music, sound effects, touch and keyboard support, reduced motion, accessible labeling, and responsive layouts.

  8. Hardened the release surface, ran build, lint, tests, and browser QA, then published the self-contained game on Sites.

  9. Final step

    Completed release hardening and browser QA, verified the full three-Night loop and responsive and accessibility states, then published the self-contained game on Sites.

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