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ARC RACE

How to play

You and an AI get the same puzzle at the same moment. Work out the hidden rule from a few examples, build the answer, and submit it. Five minutes. Three tries each. The fastest correct answer wins.

ARC-AGI-1 puzzles 386 to choose from 5:00 clock 3 attempts each

Nobody tells you the rule. The examples are the rules.

Start here

What a puzzle looks like

Every puzzle is a small grid of coloured squares. You get a few examples, each showing an input grid and the output it turns into. The same hidden rule made every one of them. Then you get a test input on its own, and your job is to build its output — every square, exactly.

Here is a real one, task 0d3d703e:

The rule: every colour is swapped for a partner — blue ↔ grey, red ↔ magenta, green ↔ yellow, sky blue ↔ maroon. Nothing moves, nothing grows; only colours change. So the test input (sky blue, blue, green) becomes maroon, grey, yellow. Notice that no single example shows every swap — you piece the rule together across all of them.

The ten colours

Every puzzle uses only these. The number is the key you press to pick it.

A round, in order

How to play

  1. Start on Easy. The difficulty menu opens on Easy: 19 puzzles that each come down to one plain rule — a rotation, a mirror, a colour swap. They're ordered gentlest first, so the top of the list is the best place to begin. Switch to Everything for all 386 when those start feeling slow.

  2. Press START RACE. The puzzle appears for you and the AI at the same instant, and a shared five-minute clock starts counting down.

  3. Study the examples. Compare each input with its output. What changed — colours, positions, size? What stayed exactly the same? On Easy you can press Stuck? Show the hint to be told the rule outright — it costs nothing but the seconds you spend reading it.

  4. Build your answer in the editor under your name. It opens all black, already set to the size the answer needs — the toolbar states that size, because the output is often a different shape from the input.

  5. Press SUBMIT ANSWER. It must match exactly — a single wrong square counts as wrong. You'll only hear “correct” or “incorrect”, and you have three tries.

  6. See the result. It appears as soon as both of you are done, or when the clock hits zero.

Controls

Building your answer

Do thisTo
09 or click a swatchPick a colour
Click or drag across squaresPaint them with the colour you picked
F then clickFlood-fill: repaint a whole connected area of one colour at once
PBack to painting single squares
Size + RESIZEChange the grid's rows and columns. It already opens at the size the answer needs, so you rarely have to touch this
COPY INPUTStart from the test input — best when the answer is the input with a few changes. It resizes the grid to match the input, so skip it when the answer is a different shape
CLEARMake every square black again
SUBMIT ANSWERUse one of your three attempts
GIVE UPEnd your run early; the AI keeps playing
Practice

Try one before you race

A real puzzle, task 6150a2bd. Look at the two examples, then paint the answer for the test input and check it.

Your answer · pick a colour, then click squares

Scoring

How you win

Your opponent

Watching the AI play

The AI sees exactly what you see — the examples and the test input — and nothing else. It never sees the answer or your work. It gets the same three attempts and the same “correct / incorrect” feedback.

Its panel shows it working: a live “Thinking about attempt 2 of 3…” timer, each answer the moment it lands with ✓ or ✗, and the rule it thinks it has found. Every attempt stays on screen as a thumbnail, so you can watch its idea change. It usually answers within a few seconds.

A fair warning: because you can see the AI's answers as they arrive, a glance at its panel can hint at the solution. For a strictly fair race, whoever runs the game can switch this off, and the AI's answers then stay hidden until your run is over.
Guidance

Tips for solving

Check the size first

Is each output the same size as its input, bigger, or smaller? That alone often narrows the rule down.

Compare colour by colour

What was added, removed, recoloured, or moved? Look for what never changes, too.

Think in shapes

Common ideas: flipping, rotating, repeating, filling enclosed areas, drawing lines, counting, keeping only the biggest object.

Test your idea on every example

A rule that explains the first example but not the third is the wrong rule. Check them all before you build.

Use Copy input and Fill

If the answer is mostly the input, copy it and fix a few squares. Fill large areas in one click.

Check before you submit

One wrong square is a wasted attempt. Scan row by row against your rule first — time is cheaper than a try.

Quick answers

Things people ask

Where do I play?
panandi.github.io/mnistpro/arc.html — any browser, nothing to install. The digit game, MNIST-PRO, is the front page. If you're running the full version with the AI server on your own computer, it's http://localhost:8000.
Is the AI given the answer?
No. The answer never leaves the server — not to your browser, and not to the AI.
Can the AI see my screen?
No. It only sees the puzzle and its own earlier attempts.
Why only three attempts?
The original ARC-AGI-1 competition scored the best of three guesses, so the race keeps that rule.
What if I run out of time?
Your run stops at 0:00 and the result is decided on what was solved by then.
Is this hard?
It's designed to be easy for people and hard for AI — but a five-minute clock makes even people sweat. Leave the difficulty on Easy for your first few races: each of those 19 puzzles was checked to be solvable by a single simple rule, and every one of them carries a hint you can reveal.
Passing it on

Explain it in one line

“It's a race against an AI on a little colour-grid puzzle. You get a few examples, nobody tells you the rule, and you have five minutes and three tries to build the answer. Fastest correct answer wins.”

Puzzles come from the public ARC-AGI-1 training set by François Chollet (Apache 2.0) — real benchmark tasks, not imitations. The two puzzles on this page are tasks 0d3d703e and 6150a2bd.