Muldle 𒀯

Play: https://bertblookers.github.io/muldle/

A daily Wordle-style game for astronomical catalogue identifiers. Each day there is one target object from the Messier, NGC, IC, Melotte, Collinder, Caldwell or Barnard catalogues; you get six guesses to find its identifier, e.g. M31, NGC42, Mel25 or NGC1023A.

How to play

• Type the full identifier: catalogue prefix (M, NGC, IC, Mel, Cr, C or B), the number without leading zeros, plus a component letter if the object has one. Tiles left empty count as blanks.
• Each object is in the game once, under the identifier most people know it by: the Andromeda Galaxy is M31, and guessing NGC224 tells you so.
• Puzzles before 5 October 2026 (#0–#26) use only NGC and IC; a puzzle you played before then keeps the zero-padded spelling it was played in (NGC0042).
• Standard Wordle colours after each guess: green = right character in the right place, yellow = elsewhere in the identifier, grey = absent.
• A hint panel describes each guessed object: constellation, object type, magnitude, and the angular distance and direction to the target.
• Click a submitted guess to see that object in a sky view (Aladin Lite); after the game the view shows the target. A Constellations button under the view draws every constellation's border, stick figure and name.
• Hard mode is on by default: every guess must be one that could still be the answer. Greens stay in place, a character can't return to a tile where it was yellow or grey, and character counts must fit the feedback (stricter than NYT Wordle's hard mode).

Modes

Toggle by the title between three modes; ID and ABC each have a daily puzzle:

• ID — guess the catalogue identifier (the default, described above).
• ABC — guess the object's well-known common name (e.g. ORION NEBULA) as a Wordle over its letters.
• OMNI — any identifier or name in the game can be the answer, from M31 to ORION NEBULA and SIRIUS; it opens once you've finished today's ID or ABC puzzle, won or lost, and plays one random puzzle after another. Spaces count; apostrophes and hyphens are shown, never typed. Mini, beside it, plays only the short answers (up to 6 characters).

More

• Puzzle navigator — the « · Puzzle #N · » control by the title browses and plays past puzzles; deep-links are shareable (?p=N).
• Stats & history (in the settings menu ⚙) — games played, win %, current and max streak, and your guess distribution, plus a list of the puzzles you've played. Everything is kept only in your own browser; nothing is ever sent anywhere.
• Share your result as an emoji grid, and watch a countdown to the next puzzle.
• Unlimited — once you've finished today's puzzle, won or lost, switch from Daily to Unlimited (beside the puzzle number) and solve random puzzles one after another, as many as you like, in either mode. A stopwatch runs from your first key; Unlimited keeps stats of its own (longest session, best solves per hour, average time per solve), and your daily streak is left alone.

Run locally

It's a static site — serve the repo root with any web server, e.g.:

python -m http.server 8080

then open http://localhost:8080. Object type/magnitude hints and the sky view need a network connection (SIMBAD and Aladin Lite are queried at runtime).

The name

MUL 𒀯 — Sumerian for "star", after the oldest known star catalogues: the Babylonian "Three Stars Each" lists (cuneiform: MUL.MEŠ 3.TA.ÀM, c. 12th century BC) and their successor MUL.APIN. The 𒀯 glyph is served as a tiny single-character subset of Noto Sans Cuneiform, since almost no system ships a cuneiform font.

Inspiration

Inspired by Wordle by Josh Wardle, now published by The New York Times. Muldle is an independent hobby project with no affiliation to or endorsement by Josh Wardle or The New York Times.

Data & attribution

The astronomical data is not covered by the code license and is credited to its sources — see ATTRIBUTION.md for the full list (VizieR catalogues VII/239A, VII/220A and VI/42, SIMBAD, Aladin Lite — all CDS, Strasbourg — OpenNGC, the Caldwell, Melotte and Collinder lists, common names from SIMBAD, OpenNGC, Wikipedia and a few NASA and magazine pages, and the Noto Sans Cuneiform font). data.js (puzzles before 5 October 2026) and data_v2.js (from then on) are generated from those sources at build time.

License

The code is licensed under the GNU Affero General Public License v3.0 — see LICENSE. SPDX: AGPL-3.0-only.