Launchway
Logic puzzle · Build 13 · Playable

Rule Out

An old sorter keeps some trays and returns the rest. Someone set it and left no note.

Works on phone, tablet and desktop · No download · No account

What it is

The machine has a setting. You build an arrangement of up to three coloured pieces, run it, and the machine answers pass or fail. Nothing else. No hints, no warmer-colder, no partial credit.

You get eight tests to work out what the setting is.

You never say the rule. You prove it.

When you think you have it, you press I've got it — and the machine asks you to demonstrate. Four arrangements in order: one it will keep, one it will return, one it will keep, one it will return.

No feedback until all four are in. You cannot feel your way through the proof the way you felt your way through the tests.

That is the whole design. Believing you know the rule and being able to produce a case it rejects are different things, and only the second one is knowledge.

Spending tests on being wrong

Eight is not many, and the instinct is to spend them confirming what you already suspect. Arrangements that pass feel like progress. They are usually the least informative thing you can do.

The tests that teach you something are the ones you expect to fail. That is uncomfortable, and it is the point of the title.

How to play

  • Put a piece on the trayTap a colour
  • Test the arrangementRun it
  • Start the proofI've got it

Nothing in the game is longer than a sentence — it is built to be read by people whose first language is not English.

What isn't settled yet

The proof works and the machine gives away nothing it shouldn't. What has not been tested is whether someone who has never met a puzzle like this understands, before their tests run out, that they are supposed to go looking for a no.

Build log

  1. Gave the machine an owner. It read as cold and arbitrary until one line fixed it — someone set it, and left no note. That makes the two starting examples answers already on the board, and makes a limited number of tests a physical fact rather than a game being stingy.

  2. Closed an exploit that seven builds had shipped.

  3. A rule is now identified by how it behaves, not by what it is called. Two differently-worded settings that accept and reject exactly the same arrangements are the same setting, and the game had been treating them as different.

Credits and licences

Built on three.js, used under the MIT licence with the copyright notice retained in the shipped file. Typefaces are licensed under the SIL Open Font Licence. Cover art was composited from a base image created with Grok (xAI).

Rule Out is original work by Launchway Games.