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One liar in every room

Usoone

The puzzle is made the moment you press. Nothing is recorded. Play full screen

In every room, exactly one number is lying. Compare their claims and catch the liar.

Made by the same generator as the app: one answer, reachable by logic alone. Hints come in three steps.

What makes it fun

  1. Two stories clash

    When two numbers cannot both be right, one is lying.

  2. Catch one, trust the rest

    One liar per room. Every other number tells the truth.

  3. Liars fall like dominoes

    One solved room exposes the liar next door.

Try one on the board above

Rules

  1. Number cells are never black. Black cells cannot touch up, down, left or right (diagonals are fine).
  2. All non-black cells, numbers included, form one group connected up, down, left and right.
  3. A number is how many black cells touch it above, below, left and right. But every room has exactly one lying number that differs from the real count.

SOLVED WHENSolved when all black cells are placed, every other cell has a white mark, and every number has ○ (honest) or × (liar).

Your first move

Look for a 0. If it is honest, every cell around it is white. Compare it with the other numbers in its room to see which one lies.

When you get stuck

Hints come in three steps: where to look, why it works, then the answer. The first step only shows the place, so you can still find the rest yourself.

Controls

Tap for black
A short tap makes a cell black.
Long-press for a white mark
Long-press a cell you know is white to mark it. Marks never count as mistakes.
Tap again to fix
Repeated taps cycle black → white mark → clear.
○ and × on numbers
Tap a number for ○, long-press it for ×. ○ and × never count as mistakes.
Undo and Redo
Step back one move at a time. Went too far? Redo brings it back.

Records and practice live in the app

The web version is for playing only and keeps no records. The app adds:

  • Ranked matches and tiers that follow your level
  • Technique training, one technique at a time, plus the basic rules
  • Your solve history, achievements and progress over time

Some techniques you can train

  • Black Cross
  • Room Single
  • Count Check
  • Honest Fill
  • Liar Dodge
  • Cut Point

STORENot on the App Store or Google Play yet. Store links will appear on this page once they are live.

App home: tier and ranked match
Ranked matches and tiers that follow your level
App training: basic rules and techniques
Technique training, one technique at a time, plus the basic rules