Can You Spot the AI's Mistake? A Free 5-Minute Coding Game
By Pooja Goenka · Published 2026-10-04 · Updated 2026-10-21
Here is a short answer an AI wrote about JSON. Four lines are true and one is not. Read it once and decide which one before you scroll.
What are the basic rules of JSON?
- JSON is a plain-text format for structured data, and most languages can read and write it.
- Object keys must be strings in double quotes, so
{name: 1}is not valid JSON.- Values can be strings, numbers, true, false, null, arrays or objects.
- You can add a comment on its own line with
//, and parsers skip it like whitespace.- A trailing comma after the last item, as in
[1, 2,], is not allowed.
It is line 4. Standard JSON has no comments at all. RFC 8259, the JSON standard, defines none, and a strict parser such as JavaScript's JSON.parse throws an error on that line. Some tools accept comments as an extension, which is exactly why the claim sounds plausible.
If you got it, you also had to resist line 5, which sounds like a fussy rule someone made up and is in fact correct. The game asks for both, five times in a row.
Why practise this at all
More and more of the code and explanations engineers work with now start as an AI draft. So as well as producing answers, you need to be able to read a fluent, well-structured one and notice the sentence that would cause a bug if you shipped it. I wrote about why confident wrong answers are the most useful thing to practise on separately.
Normal quizzes are a poor way to drill this, because a quiz question tells you something is being tested. In this game the wrong line looks exactly like the right ones.
How Spot Aria's Mistake works
Spot Aria's Mistake is a free game on LogicWiz Arena. Aria, an AI, answers a question in five lines, and one line is wrong.
A game is five rounds, about five minutes in all, on a track you pick: AI, Python, Frontend, Backend and APIs, SQL and databases, Data engineering, Cloud and DevOps, or DSA and OOP.
In each round the lines appear at reading pace. The clock starts after the last line, and you have 20 seconds to tap the wrong one. Then you say why it is wrong, choosing from three explanations, with 15 seconds to decide. You score 100 points for the right line, 50 for the right reason, and a speed bonus of up to 100 if you are quick.
Every player gets a certificate with a badge, so a first try is worth finishing.
The October Open
The most recent event, the October Open, ran until 19 October and has now ended. It was open to everyone, one entry per person, and the top 10 on the scoreboard won free LogicWiz goodies. The game itself stays free to play, and the Arena home page has a free practice round that needs no sign-in at all.
Tips from the sample round
Every line sounds equally confident and the wrong one has no hedging words, so judge each claim and ignore the tone.
Be suspicious of a rule that sounds convenient. Line 4 was wrong because it describes what we would like JSON to allow.
Don't overcorrect either. Line 5 sounds pedantic and is true, and calling something wrong when it is right costs you the round.
Once you have picked a line, say the reason to yourself before you see the options. The wrong reasons are written to be tempting.
Common questions
Is Spot Aria's Mistake free?
Yes. The game is free to play, and the October Open was free to enter.
Do I need an account?
You can try a practice round on the event page without one. To play the scored event you sign in with Google, because each person gets one entry.
Which topics are covered?
Tracks: AI, Python, Frontend, Backend and APIs, SQL and databases, Data engineering, Cloud and DevOps, and DSA and OOP. You pick one before you start.
How long does a game take?
About five minutes for five rounds.
What do I get for playing?
Every player gets a certificate with a badge. In the October Open, the top 10 on the scoreboard won free LogicWiz goodies.