Run Detail

completedclaude-opus-5

Unscored

Every model's answer from this round

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Provider

openrouter

Challenge Version

v1.0

Turns

Duration

Batched — not timed

Total Tokens

10,466

Input Tokens

2,166

Output Tokens

8,300

Reasoning Tokens

1,797

Reasoning Effort

medium

Est. Cost

$0.1092

Started

8/26/2026, 11:05:00 AM

OR Provider

Anthropic

Finish Reason

stop

Generation ID

gen-batch-1787742301-840621f75d4e7fc85370

Turns (1)

Turn #1

2,166 in8,300 out1,797 reasoning10,466 total

user

Turn Two Cards

Build a memory game — also called concentration or pairs — as one self-contained HTML page.

The theme is fascinating animals. You choose the eight animals and the art style.

The game

A 4×4 board: 16 cards, all face down.
8 animals, each on exactly 2 cards.
Clicking a face-down card turns it face up.
At most two cards are face up at once.
If the two match, they stay face up.
If they do not match, they turn face down again after a short pause.
The game is won when all 8 pairs are face up.
Card positions are shuffled at the start of every game.

The player must be able to see how many moves they have made and how many pairs are left.

When a pair is matched, show that animal's fact.

When the game is won, say so clearly.

Controls

Clicking a card is the main interaction.

You may add exactly one button: New game.

Do not add:

A difficulty selector
A board-size selector
A timer setting
A menu or settings panel

The animals

Choose 8 animals that are genuinely fascinating — something about each one is strange, extreme, or surprising.

For each animal, provide:

A name
An art prompt
One fact, 120 characters or fewer, shown when its pair is matched

The facts must be true. They will be checked.

Do not use the eight most obvious zoo animals. Lion, tiger, elephant, giraffe, panda, penguin, dolphin and zebra are all forbidden.

Artwork

You do not create the artwork yourself. You write the prompts, and an image model draws them afterwards.

The art is delivered as one PNG:

art/cards.png

The file is a 2048×2048 3×3 contact sheet:

9 cells
Cells numbered 0–8
Numbering goes left-to-right, top-to-bottom
Cells 0–7 are the eight animals
Cell 8 is the card back — one design, shown on every face-down card
One subject centered in each cell
Flat black background
All cells rendered at the same scale

The grid layout, numbering, and background are fixed. Your job is to specify what belongs in each cell.

The path art/cards.png must appear exactly once in your HTML.

You may slice it with CSS background positioning, a canvas, clipped elements, or another technique.

Because the PNG has a black background, make sure the artwork sits properly on your card design.

Missing artwork

The game must be playable before art/cards.png exists.

If the image cannot be loaded, each face-up card must show a readable fallback — the animal's name, a drawn shape, or a styled placeholder. Blank cards are not acceptable, because a memory game with blank faces cannot be played at all.

Optional extra art

You may request one additional image, such as a table surface or background.

It must use the form art/<id>.png and it must be optional decoration — the page must look finished without it.

URL test mode

The page must support one URL mode.

`#demo`

Deal a board where 7 of the 8 pairs are already matched and only one pair is left to find.

This exists so the win can be filmed without playing a whole game.

It must be a real board state that the normal game logic plays out — not a fake animation.

Technical restrictions

The game must be a single HTML file.

It must:

Work offline
Run by double-clicking the HTML file
Require no build step
Use no CDN
Use no framework
Use no external stylesheet
Use no external fonts
Use no external scripts
Use no external images except the specified art/ files
Make no network requests at runtime

Do not use:

localStorage
sessionStorage
Cookies
indexedDB

The page must have no scrollbars at any window size. The board should scale to fit whatever space it is given.

Sound is optional. If you add any, generate it with the Web Audio API — no audio files.

Things to avoid

Emoji, anywhere. Not as card faces, not as buttons, not as decoration.
Card faces made of text or symbols instead of the artwork.
A board that reflows into a single column and has to be scrolled.

Required response

Your response must contain exactly these four sections.

The pitch

One line: what the game is called and what it looks like.

The game

Provide exactly one fenced html code block containing the complete HTML page and nothing else.

The art

Provide exactly one fenced json code block using this structure:

{
  "game": { "name": "TURN TWO CARDS" },
  "sheet": {
    "style": "One paragraph, appended to every cell prompt below: medium, palette, lighting, line quality. This is what makes nine separate images look like one deck.",
    "cells": [
      {
        "cell": 0,
        "id": "axolotl",
        "name": "Axolotl",
        "role": "animal",
        "prompt": "What to draw in this cell. One animal.",
        "fact": "It regrows lost limbs, and even parts of its brain, without scarring."
      },
      { "cell": 8, "id": "back", "name": "Card back", "role": "back", "prompt": "The pattern on the back of every card." }
    ]
  },
  "extras": [{ "id": "table", "aspect": "16:9", "prompt": "..." }]
}

Rules:

cells contains exactly 9 entries.
cell values are 0–8 with no gaps or duplicates.
Cells 0–7 have "role": "animal" and a fact.
Cell 8 has "role": "back" and no fact.
id is a single lowercase token and is unique.
fact is 120 characters or fewer.
extras may contain at most one entry, or be left out.
aspect must be one of: 16:9, 9:16, 1:1, 3:2, 2:3, 4:3, 3:4

The JSON block must contain no prose and no comments, because it is parsed automatically.

The notes

Four bullets:

Before the art arrives: what a card face shows while art/cards.png is unavailable.
On a win: what happens.
Mismatch delay: how long two unmatched cards stay face up, and why you chose that.
Fact sources: one line on how confident you are in the eight facts.

assistant

The pitch

TURN TWO CARDS: Strange Beasts — a 4×4 deck of luminous ink-and-gouache animal portraits on deep teal cards, dealt onto a dark table, with a fact ribbon that lights up whenever a pair meets its twin.

The game

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>Turn Two Cards — Strange Beasts</title>
<style>
  :root{
    --sheet: url("art/cards.png");
    --ink:#eaf3f2;
    --card:#0e3a3c;
    --card2:#12525a;
    --gold:#e9c46a;
  }
  *{box-sizing:border-box;margin:0;padding:0}
  html,body{height:100%;overflow:hidden}
  body{
    background:#07100f;
    color:var(--ink);
    font-family:"Trebuchet MS",Verdana,Geneva,sans-serif;
    display:flex;flex-direction:column;
    -webkit-tap-highlight-color:transparent;
  }
  #table{
    position:fixed;inset:0;z-index:-1;
    background:
      radial-gradient(ellipse at 50% 35%,#123033 0%,#07100f 70%),
      url("art/table.png") center/cover no-repeat;
    background-blend-mode:soft-light,normal;
    opacity:.95;
  }
  header{
    flex:0 0 auto;
    display:flex;align-items:center;justify-content:center;
    gap:clamp(8px,2vw,26px);
    flex-wrap:wrap;
    padding:clamp(6px,1.4vh,14px) 12px clamp(2px,.8vh,8px);
  }
  h1{
    font-size:clamp(13px,2.1vh,20px);
    letter-spacing:.22em;font-weight:700;
    color:var(--gold);text-transform:uppercase;white-space:nowrap;
  }
  .stat{
    font-size:clamp(11px,1.8vh,16px);
    letter-spacing:.1em;text-transform:uppercase;opacity:.9;white-space:nowrap;
  }
  .stat b{color:#fff;font-size:1.15em}
  button{
    font:inherit;font-size:clamp(11px,1.7vh,15px);
    letter-spacing:.14em;text-transform:uppercase;
    color:#07100f;background:var(--gold);
    border:0;border-radius:999px;
    padding:.45em 1.2em;cursor:pointer;
  }
  button:hover{background:#f6dc9a}
  #wrap{flex:1 1 auto;min-height:0;display:flex;align-items:center;justify-content:center;padding:4px}
  #board{
    display:grid;
    grid-template-columns:repeat(4,1fr);
    grid-template-rows:repeat(4,1fr);
    gap:clamp(4px,1vmin,12px);
  }
  .card{position:relative;perspective:900px;cursor:pointer}
  .card.done,.card.up{cursor:default}
  .inner{
    position:absolute;inset:0;
    transform-style:preserve-3d;
    transition:transform .42s cubic-bezier(.4,.1,.3,1);
    border-radius:9%;
  }
  .card.up .inner,.card.done .inner{transform:rotateY(180deg)}
  .side{
    position:absolute;inset:0;
    backface-visibility:hidden;-webkit-backface-visibility:hidden;
    border-radius:9%;
    overflow:hidden;
    box-shadow:0 3px 10px rgba(0,0,0,.55);
  }
  .back{
    background-color:var(--card2);
    background-image:var(--sheet);
    background-size:300% 300%;
    background-position:100% 100%;
    border:2px solid #2b7c81;
  }
  body.no-art .back{
    background-image:
      repeating-linear-gradient(45deg,#12525a 0 8px,#0e3a3c 8px 16px);
  }
  .face{
    transform:rotateY(180deg);
    background-color:#000;
    background-image:var(--sheet);
    background-size:300% 300%;
    background-repeat:no-repeat;
    border:2px solid #3d8c86;
    display:flex;align-items:flex-end;justify-content:center;
  }
  body.no-art .face{background-image:none;background-color:#0d2b30;align-items:center}
  .label{
    display:none;
    width:100%;padding:6% 4%;
    text-align:center;font-weight:700;
    font-size:clamp(8px,1.6vmin,15px);
    letter-spacing:.06em;text-transform:uppercase;
    color:var(--gold);
    text-shadow:0 1px 2px #000;
  }
  body.no-art .label{display:block}
  .card.done .face{border-color:var(--gold);box-shadow:0 0 0 2px rgba(233,196,106,.45),0 3px 10px rgba(0,0,0,.55)}
  footer{
    flex:0 0 auto;
    min-height:clamp(38px,7.5vh,72px);
    display:flex;align-items:center;justify-content:center;
    padding:4px clamp(10px,4vw,40px) clamp(8px,1.6vh,18px);
    text-align:center;
  }
  #msg{
    max-width:70ch;
    font-size:clamp(11px,2vh,18px);
    line-height:1.35;
  }
  #msg .who{color:var(--gold);font-weight:700;letter-spacing:.08em;text-transform:uppercase}
  #msg.win{color:var(--gold);font-weight:700;letter-spacing:.1em;font-size:clamp(13px,2.6vh,24px)}
</style>
</head>
<body>
<div id="table" aria-hidden="true"></div>

<header>
  <h1>Turn Two Cards</h1>
  <div class="stat">Moves <b id="moves">0</b></div>
  <div class="stat">Pairs left <b id="left">8</b></div>
  <button id="new">New game</button>
</header>

<div id="wrap"><div id="board" role="grid" aria-label="Memory board"></div></div>

<footer><div id="msg">Turn over two cards. Find the eight strange beasts.</div></footer>

<script>
const ANIMALS=[
 {cell:0,name:"Axolotl",fact:"It regrows lost limbs, and even parts of its brain, without leaving a scar."},
 {cell:1,name:"Mantis Shrimp",fact:"Its club punches so fast the water briefly boils into collapsing bubbles."},
 {cell:2,name:"Naked Mole-Rat",fact:"It can live 30 years and survive about 18 minutes with no oxygen at all."},
 {cell:3,name:"Pangolin",fact:"The only mammal armoured in keratin scales; toothless, it laps up ants with a very long tongue."},
 {cell:4,name:"Tardigrade",fact:"Dried almost water-free, it survives boiling, freezing, radiation and the vacuum of space."},
 {cell:5,name:"Platypus",fact:"A venomous, egg-laying mammal that hunts with eyes shut, sensing prey's electric fields."},
 {cell:6,name:"Immortal Jellyfish",fact:"Turritopsis dohrnii can rewind its life cycle, reverting to a polyp instead of dying."},
 {cell:7,name:"Bombardier Beetle",fact:"It mixes chemicals in its abdomen and sprays a near-boiling, pulsing jet at attackers."}
];

const boardEl=document.getElementById('board'),
      movesEl=document.getElementById('moves'),
      leftEl=document.getElementById('left'),
      msgEl=document.getElementById('msg'),
      wrapEl=document.getElementById('wrap');

let deck=[],first=null,second=null,lock=false,moves=0,matched=0;
let audio=null;

function beep(freqs,dur){
  try{
    if(!audio) audio=new (window.AudioContext||window.webkitAudioContext)();
    const t=audio.currentTime;
    freqs.forEach((f,i)=>{
      const o=audio.createOscillator(),g=audio.createGain();
      o.type='triangle';o.frequency.value=f;
      g.gain.setValueAtTime(0.0001,t+i*0.05);
      g.gain.exponentialRampToValueAtTime(0.16,t+i*0.05+0.02);
      g.gain.exponentialRampToValueAtTime(0.0001,t+i*0.05+dur);
      o.connect(g).connect(audio.destination);
      o.start(t+i*0.05);o.stop(t+i*0.05+dur+0.05);
    });
  }catch(e){}
}

function pos(cell){
  const c=cell%3,r=Math.floor(cell/3);
  return (c*50)+"% "+(r*50)+"%";
}

function shuffle(a){
  for(let i=a.length-1;i>0;i--){const j=Math.floor(Math.random()*(i+1));[a[i],a[j]]=[a[j],a[i]];}
  return a;
}

function build(demo){
  deck=shuffle(ANIMALS.concat(ANIMALS).map(a=>({a})));
  first=second=null;lock=false;moves=0;matched=0;
  boardEl.innerHTML='';
  msgEl.className='';
  msgEl.textContent="Turn over two cards. Find the eight strange beasts.";

  deck.forEach((card,i)=>{
    const el=document.createElement('div');
    el.className='card';el.setAttribute('role','gridcell');
    el.dataset.i=i;
    el.innerHTML='<div class="inner">'+
      '<div class="side back"></div>'+
      '<div class="side face" style="background-position:'+pos(card.a.cell)+'">'+
      '<span class="label">'+card.a.name+'</span></div></div>';
    el.addEventListener('click',()=>flip(i));
    card.el=el;
    boardEl.appendChild(el);
  });

  if(demo){
    // a real board state: 7 pairs already found by normal rules
    const hidden=ANIMALS[Math.floor(Math.random()*ANIMALS.length)];
    deck.forEach(c=>{
      if(c.a!==hidden){c.done=true;c.el.classList.add('done');}
    });
    matched=7;moves=11;
    msgEl.innerHTML='<span class="who">Seven pairs down.</span> One pair left to find.';
  }
  update();
  layout();
}

function update(){
  movesEl.textContent=moves;
  leftEl.textContent=8-matched;
}

function flip(i){
  const c=deck[i];
  if(lock||c.done||c===first) return;
  if(second) return;
  c.el.classList.add('up');
  beep([520],0.09);
  if(!first){first=c;return;}
  second=c;moves++;update();
  if(first.a===second.a){
    const a=first.a;
    setTimeout(()=>{
      [first,second].forEach(x=>{x.done=true;x.el.classList.remove('up');x.el.classList.add('done');});
      first=second=null;
      matched++;update();
      beep([660,880],0.16);
      if(matched===8){
        msgEl.className='win';
        msgEl.textContent="You won! All eight pairs found in "+moves+" moves.";
        beep([660,880,1100,1320],0.22);
      }else{
        msgEl.className='';
        msgEl.innerHTML='<span class="who">'+a.name+'</span> — '+a.fact;
      }
    },260);
  }else{
    lock=true;
    setTimeout(()=>{
      [first,second].forEach(x=>x.el.classList.remove('up'));
      first=second=null;lock=false;
    },1100);
  }
}

function layout(){
  const w=wrapEl.clientWidth-8,h=wrapEl.clientHeight-8;
  const s=Math.max(120,Math.min(w,h));
  boardEl.style.width=s+'px';
  boardEl.style.height=s+'px';
}
window.addEventListener('resize',layout);

document.getElementById('new').addEventListener('click',()=>{
  history.replaceState(null,'',location.pathname+location.search);
  build(false);
});

// artwork probe
const probe=new Image();
probe.onerror=()=>document.body.classList.add('no-art');
probe.src=getComputedStyle(document.documentElement)
  .getPropertyValue('--sheet').trim().replace(/^url\(["']?/,'').replace(/["']?\)$/,'');

build(location.hash.toLowerCase()==='#demo');
</script>
</body>
</html>

The art

{
  "game": { "name": "TURN TWO CARDS" },
  "sheet": {
    "style": "Painted in luminous ink and gouache on a flat pure-black background: a single centered subject per cell, three-quarter view, full body inside the cell with generous margins, confident dark outlines with fine hatched detail, glowing rim light from the upper left, restrained palette of deep teal, jade, warm gold, coral and bone white, subtle bioluminescent accents, no text, no borders, no drop shadows, no ground plane, all nine subjects drawn at the same scale and same line weight so they read as one deck of cards.",
    "cells": [
      {
        "cell": 0,
        "id": "axolotl",
        "name": "Axolotl",
        "role": "animal",
        "prompt": "A pale pink axolotl floating with feathery coral-red external gills fanned out, wide smiling mouth, tiny stubby legs, tail curved gently.",
        "fact": "It regrows lost limbs, and even parts of its brain, without leaving a scar."
      },
      {
        "cell": 1,
        "id": "mantisshrimp",
        "name": "Mantis Shrimp",
        "role": "animal",
        "prompt": "A peacock mantis shrimp in profile, iridescent teal and coral banded armour, stalked compound eyes raised, one raptorial club cocked to strike.",
        "fact": "Its club punches so fast the water briefly boils into collapsing bubbles."
      },
      {
        "cell": 2,
        "id": "molerat",
        "name": "Naked Mole-Rat",
        "role": "animal",
        "prompt": "A wrinkled hairless naked mole-rat, pinkish-grey loose skin, tiny eyes, two prominent protruding front incisors, whiskered snout, standing low.",
        "fact": "It can live 30 years and survive about 18 minutes with no oxygen at all."
      },
      {
        "cell": 3,
        "id": "pangolin",
        "name": "Pangolin",
        "role": "animal",
        "prompt": "A pangolin walking, body covered in overlapping bronze keratin scales, long tapered tail, small conical head, long sticky tongue extended slightly.",
        "fact": "The only mammal armoured in keratin scales; toothless, it laps up ants with a very long tongue."
      },
      {
        "cell": 4,
        "id": "tardigrade",
        "name": "Tardigrade",
        "role": "animal",
        "prompt": "A giant microscope-style tardigrade, plump segmented translucent body, eight stubby clawed legs, round puckered mouth, faint internal glow.",
        "fact": "Dried almost water-free, it survives boiling, freezing, radiation and the vacuum of space."
      },
      {
        "cell": 5,
        "id": "platypus",
        "name": "Platypus",
        "role": "animal",
        "prompt": "A platypus swimming, dark brown waterproof fur, broad soft duck-like bill, webbed forefeet, flat beaver-like tail, eyes closed.",
        "fact": "A venomous, egg-laying mammal that hunts with eyes shut, sensing prey's electric fields."
      },
      {
        "cell": 6,
        "id": "jellyfish",
        "name": "Immortal Jellyfish",
        "role": "animal",
        "prompt": "A tiny transparent Turritopsis jellyfish, bell-shaped dome with glowing red stomach, dozens of fine trailing tentacles, soft bioluminescent halo.",
        "fact": "Turritopsis dohrnii can rewind its life cycle, reverting to a polyp instead of dying."
      },
      {
        "cell": 7,
        "id": "bombardier",
        "name": "Bombardier Beetle",
        "role": "animal",
        "prompt": "A bombardier beetle in three-quarter view, glossy blue-black elytra, rust-orange head and legs, abdomen tip aimed back firing a small hot vapour jet.",
        "fact": "It mixes chemicals in its abdomen and sprays a near-boiling, pulsing jet at attackers."
      },
      {
        "cell": 8,
        "id": "back",
        "name": "Card back",
        "role": "back",
        "prompt": "A symmetrical card-back emblem: a gold ring of interlocking scale and tentacle motifs around a single stylised teal eye, filling the cell evenly on black."
      }
    ]
  },
  "extras": [
    {
      "id": "table",
      "aspect": "16:9",
      "prompt": "A dark green baize tabletop lit softly from above, faint woven texture and a subtle vignette, no objects, no text, very low contrast so it works as background decoration."
    }
  ]
}

The notes

Before the art arrives: an Image probe on art/cards.png fails and adds a no-art class — face-up cards become deep teal panels with the animal's name in gold capitals, and card backs become a diagonal teal stripe pattern, so the game is fully playable.
On a win: the eighth match locks all sixteen cards face up with gold borders, a rising four-note chord plays, and the ribbon states "You won! All eight pairs found in N moves."
Mismatch delay: 1100 ms — long enough to read and memorise two positions, short enough that a full game never feels like waiting; matches resolve faster, at 260 ms.
Fact sources: high confidence — all eight are well-documented (axolotl regeneration, mantis shrimp cavitation, naked mole-rat anoxia tolerance and 30-year lifespan, pangolin keratin scales, tardigrade cryptobiosis in vacuum, platypus electroreception and venom, Turritopsis dohrnii reverse development, bombardier beetle pulsed ~100 °C spray) and each is phrased conservatively.

Attachments

anthropic/claude-opus-5 — page