Support & FAQ

Doublet · Quiet Paper Studio · ACG Apps

Need help?

Email support@acgapps.org. Include your device + OS version and a short description of what happened. We usually reply within a day or two.

How do I play?

Doublet is Lewis Carroll's 1879 word-ladder puzzle. You're shown a start word at the top and a target word at the bottom, with empty slots in between. Fill each slot with a word that changes exactly one letter from the slot above and is a real word in the dictionary. The last filled slot must be one letter away from the target.

Example: HEAD → HEAL → TEAL → TELL → TALL → TAIL

Each completed word slides a definition card in underneath. Tap any filled word to see the full dictionary entry.

What if I'm stuck?

Tap the Hint button at the bottom. Each tap reveals more:

  1. First tap: the meaning of the next word
  2. Second tap: which letter position will change
  3. Third tap: what the letter will be
  4. Fourth tap: the full word fills in

Hints are unlimited and free.

Where is my progress saved?

On your device, in the browser/app's local storage. Solved ladders, partially-filled puzzles, learned-word counts, dictionary cache, theme, and language preference all live there. Nothing is uploaded.

That means: if you switch phones or reinstall, your progress doesn't follow (yet). Cloud sync may come in a later release, opt-in.

I played in another language. How do I switch?

Settings → Language. Doublet ships in English, French, and German. Each language has its own dictionary, its own ladder set, and its own definition card language. Your solved-ladder count is tracked per-language.

I solved a ladder. Why is it blank when I come back?

Solved ladders save their solution words. If you don't see them on return, you may be on an old build before the save-solution feature shipped (mid-May 2026). Solve the ladder again; the new version will save the path.

On a solved ladder, the bottom button reads Reset (not Restart). Tap it only if you want to wipe your saved solution and play that ladder again from scratch.

I bought the unlock. Does it work on my other device?

Yes, on the same platform account (the same Google account on Android, or same Apple ID on iOS). On a new device, install Doublet, then tap Settings → Restore purchase.

Note: Android and iOS purchases are separate (different stores). Doublet is a one-time USD $0.99 on each.

How do I reset everything?

Settings → Reset progress…. This wipes every solved ladder, every partially-filled attempt, every learned-word count, and the dictionary cache. It does not affect your purchase (the unlock persists on your platform account).

I think there's a bug.

Email support@acgapps.org with:

Bug reports actually make the app better — thank you in advance.

The dictionary card doesn't appear for some words.

Doublet fetches definitions from Wiktionary. Some rare, archaic, or very technical words don't have Wiktionary entries; the card will read "(definition unavailable)" for those. If you suspect a word should have an entry but doesn't appear, drop us a note — sometimes our parser struggles with unusual Wiktionary page formatting and we can adjust.

Why is this app called Doublet?

Lewis Carroll invented this puzzle in 1879 and named it a "Doublet." The format ran in Vanity Fair magazine for several years. Carroll's original 4-step example turned HEAD into TAIL through HEAR, HEAT, HELT, … actually no, that's wrong — Carroll's worked.

The mechanic is in the public domain; the app's implementation, content, and design are by Quiet Paper Studio.