Visual acuity — 8px

what this tests

Read a requested 5-character group off a randomly generated eye chart, rendered at 8px — near the floor of what current vision models resolve.

An eye chart for machines: the same task at shrinking sizes finds the resolution floor where reading breaks down. Every chart is generated fresh per run, so the characters can't be memorized.

Grading: Exact match on the 5 characters, case-insensitive.

sample image · fixed demo seed, never used in live runs

Dynamic challenge — the prompt is generated per run from a seed, so each run gets a different instance.

generate

(function (a) {
function svgDocument(width, height, body, fill = "#fffdf8") {
    return `<svg xmlns="http://www.w3.org/2000/svg" width="${width}" height="${height}" viewBox="0 0 ${width} ${height}"><rect width="100%" height="100%" fill="${fill}"/>${body}</svg>`;
}
function shapeSvg(shape, x, y, color, size) {
    if (shape === "circle")
        return `<circle cx="${x}" cy="${y}" r="${size}" fill="${color}"/>`;
    if (shape === "square")
        return `<rect x="${x - size}" y="${y - size}" width="${size * 2}" height="${size * 2}" rx="3" fill="${color}"/>`;
    if (shape === "diamond")
        return `<path d="M ${x} ${y - size} L ${x + size} ${y} L ${x} ${y + size} L ${x - size} ${y} Z" fill="${color}"/>`;
    return `<path d="M ${x} ${y - size} L ${x + size} ${y + size} L ${x - size} ${y + size} Z" fill="${color}"/>`;
}


const MASK64 = (1n << 64n) - 1n;
const GOLDEN_GAMMA = 0x9e3779b97f4a7c15n;
function createRng(seed) {
    let state = seed & MASK64;
    return () => {
        state = (state + GOLDEN_GAMMA) & MASK64;
        let z = state;
        z = ((z ^ (z >> 30n)) * 0xbf58476d1ce4e5b9n) & MASK64;
        z = ((z ^ (z >> 27n)) * 0x94d049bb133111ebn) & MASK64;
        z = z ^ (z >> 31n);
        return Number(z >> 11n) / 9007199254740992;
    };
}
function pick(rnd, arr) {
    return arr[Math.floor(rnd() * arr.length)];
}
function int(rnd, lo, hi) {
    return lo + Math.floor(rnd() * (hi - lo + 1));
}
const ACUITY_CHARSET = "ABCDEFGHJKMNPQRSTUVWXYZ23456789".split("");
const EYE_CHART_ROW_SIZES = [56, 40, 28, 20, 14, 10, 8];
const COLOR_NAMES = [
    ["blue", "#2463eb"],
    ["red", "#dc2626"],
    ["green", "#16a34a"],
    ["orange", "#f26a22"],
    ["purple", "#7c3aed"],
    ["teal", "#0891b2"],
];
const SHAPE_NAMES = ["circle", "square", "triangle", "diamond"];
const MONTHS = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug"];
const PRODUCT_NAMES = [
    "Wireless Mouse", "USB-C Cable", "Notebook", "Desk Lamp", "Coffee Mug",
    "Phone Stand", "Water Bottle", "Backpack", "Keyboard", "Screen Cleaner",
    "Sticky Notes", "Ballpoint Pen", "Laptop Sleeve", "Mouse Pad", "Headphones",
];
const CHART_TEMPLATES = [
    { title: "Monthly Active Users", subtitle: "Unique users per month, in thousands", yAxisLabel: "Thousand users" },
    { title: "Website Sessions", subtitle: "Sessions per month, in thousands", yAxisLabel: "Thousand sessions" },
    { title: "Support Tickets Opened", subtitle: "New tickets per month", yAxisLabel: "Tickets" },
    { title: "Units Shipped", subtitle: "Warehouse shipments per month, in hundreds", yAxisLabel: "Hundred units" },
    { title: "New Signups", subtitle: "New account signups per month", yAxisLabel: "Signups" },
    { title: "Server Incidents", subtitle: "Reported incidents per month", yAxisLabel: "Incidents" },
];
const VISION_FAMILIES = [
    "acuity-48", "acuity-24", "acuity-12", "acuity-8",
    "counting", "spatial", "chart", "screenshot",
];
const ACUITY_TARGET_ROW = {
    "acuity-48": 4,
    "acuity-24": 5,
    "acuity-12": 6,
    "acuity-8": 7,
};
function acuityAnswer(rnd, family) {
    const rows = [];
    for (let r = 0; r < EYE_CHART_ROW_SIZES.length; r += 1) {
        const groups = [];
        for (let g = 0; g < 3; g += 1) {
            let code = "";
            for (let i = 0; i < 5; i += 1)
                code += pick(rnd, ACUITY_CHARSET);
            groups.push(code);
        }
        rows.push(groups);
    }
    const targetRow = ACUITY_TARGET_ROW[family];
    const targetGroup = int(rnd, 1, 3);
    const expectedAnswer = rows[targetRow - 1][targetGroup - 1];
    return {
        family,
        prompt: `This is an eye chart with 7 numbered rows, each containing 3 groups of 5 characters. ` +
            `Read row ${targetRow}, group ${targetGroup} (groups are numbered left to right). What are the 5 characters, in order?`,
        expectedAnswer,
        width: 1366,
        height: 768,
        rows,
        targetRow,
        targetGroup,
    };
}
function countingAnswer(rnd) {
    const [targetColorName, targetColorHex] = pick(rnd, COLOR_NAMES);
    const targetShape = pick(rnd, SHAPE_NAMES);
    const n = int(rnd, 5, 14);
    const distractorCount = int(rnd, 6, 10);
    const total = n + distractorCount;
    const slots = [];
    for (let row = 0; row < 4; row += 1) {
        for (let col = 0; col < 6; col += 1) {
            slots.push([160 + col * 180, 180 + row * 190]);
        }
    }
    const shuffled = [...slots];
    for (let i = shuffled.length - 1; i > 0; i -= 1) {
        const j = int(rnd, 0, i);
        [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
    }
    const used = shuffled.slice(0, total);
    const distractorOptions = COLOR_NAMES.filter(([name]) => name !== targetColorName).flatMap(([, hex]) => SHAPE_NAMES.filter((shape) => !(shape === targetShape && hex === targetColorHex)).map((shape) => [shape, hex]));
    const items = [];
    for (let i = 0; i < total; i += 1) {
        const [x, y] = used[i];
        const jitterX = int(rnd, -20, 20);
        const jitterY = int(rnd, -20, 20);
        if (i < n) {
            items.push({ x: x + jitterX, y: y + jitterY, shape: targetShape, color: targetColorHex });
        }
        else {
            const [shape, hex] = pick(rnd, distractorOptions);
            items.push({ x: x + jitterX, y: y + jitterY, shape, color: hex });
        }
    }
    return {
        family: "counting",
        prompt: `How many ${targetColorName} ${targetShape}s are in the image?`,
        expectedAnswer: String(n),
        width: 1200,
        height: 900,
        items,
    };
}
function spatialAnswer(rnd) {
    const targetRow = int(rnd, 0, 4);
    const targetCol = int(rnd, 0, 4);
    const nonRedColors = COLOR_NAMES.filter(([name]) => name !== "red").map(([, hex]) => hex);
    const cells = [];
    for (let row = 0; row < 5; row += 1) {
        for (let col = 0; col < 5; col += 1) {
            if (row === targetRow && col === targetCol) {
                cells.push({ shape: "circle", color: "#dc2626" });
            }
            else {
                cells.push({ shape: pick(rnd, SHAPE_NAMES), color: pick(rnd, nonRedColors) });
            }
        }
    }
    return {
        family: "spatial",
        prompt: "Which cell contains the red circle?",
        expectedAnswer: `row ${targetRow + 1}, column ${targetCol + 1}`,
        width: 1200,
        height: 1200,
        cells,
    };
}
const CHART_YMAX = 100;
const CHART_YTICK = 20;
const CHART_QUESTION_KINDS = ["approx-value", "count-above", "approx-diff", "title"];
function drawChartValues(rnd) {
    let values;
    do {
        values = MONTHS.map(() => int(rnd, 10, 95));
    } while (values.some((v) => v % CHART_YTICK === 0));
    return values;
}
const COUNT_ABOVE_MIN_MARGIN = 6;
function chartAnswer(rnd) {
    const template = pick(rnd, CHART_TEMPLATES);
    let values = drawChartValues(rnd);
    const base = {
        family: "chart",
        width: 1200,
        height: 800,
        title: template.title,
        subtitle: template.subtitle,
        yAxisLabel: template.yAxisLabel,
        values,
        yMax: CHART_YMAX,
        yTick: CHART_YTICK,
    };
    const questionKind = pick(rnd, CHART_QUESTION_KINDS);
    switch (questionKind) {
        case "approx-value": {
            const idx = int(rnd, 0, MONTHS.length - 1);
            return {
                ...base,
                questionKind,
                tolerance: 5,
                prompt: `Using the "${template.title}" chart, approximately what value did ${MONTHS[idx]} have? ` +
                    `Read it off the y-axis; answers within +/-5 are accepted.`,
                expectedAnswer: String(values[idx]),
            };
        }
        case "count-above": {
            const MAX_THRESHOLD_ATTEMPTS = 200;
            let threshold = 0;
            let count = 0;
            let margin = 0;
            let attempts = 0;
            do {
                if (attempts > 0 && attempts % MAX_THRESHOLD_ATTEMPTS === 0) {
                    values.splice(0, values.length, ...drawChartValues(rnd));
                }
                threshold = int(rnd, 15, 90);
                count = values.filter((v) => v > threshold).length;
                margin = Math.min(...values.map((v) => Math.abs(v - threshold)));
                attempts += 1;
            } while (count === 0 || count === values.length || margin < COUNT_ABOVE_MIN_MARGIN);
            return {
                ...base,
                questionKind,
                tolerance: 0,
                prompt: `Using the "${template.title}" chart, how many months had a value greater than ${threshold}? Answer with just the number.`,
                expectedAnswer: String(count),
            };
        }
        case "approx-diff": {
            let i = 0;
            let j = 0;
            do {
                i = int(rnd, 0, MONTHS.length - 1);
                j = int(rnd, 0, MONTHS.length - 1);
            } while (i === j);
            const diff = Math.abs(values[i] - values[j]);
            return {
                ...base,
                questionKind,
                tolerance: 8,
                prompt: `Using the "${template.title}" chart, approximately what is the difference in value between ${MONTHS[i]} and ${MONTHS[j]}? ` +
                    `Answers within +/-8 are accepted.`,
                expectedAnswer: String(diff),
            };
        }
        case "title":
            return {
                ...base,
                questionKind,
                tolerance: 0,
                prompt: "What is the title shown at the top of this chart?",
                expectedAnswer: template.title,
            };
    }
}
function screenshotAnswer(rnd) {
    const itemCount = int(rnd, 3, 5);
    const namesPool = [...PRODUCT_NAMES];
    const items = [];
    for (let i = 0; i < itemCount; i += 1) {
        const idx = int(rnd, 0, namesPool.length - 1);
        const [name] = namesPool.splice(idx, 1);
        const qty = int(rnd, 1, 4);
        const priceCents = int(rnd, 499, 4999);
        items.push({ name, qty, price: priceCents / 100 });
    }
    const total = items.reduce((sum, item) => sum + item.qty * item.price, 0);
    return {
        family: "screenshot",
        prompt: "What is the total amount shown in the cart panel?",
        expectedAnswer: `$${total.toFixed(2)}`,
        width: 1400,
        height: 1000,
        items,
    };
}
function computeFixtureAnswer(input) {
    const rnd = createRng(input.seed);
    switch (input.family) {
        case "acuity-48":
        case "acuity-24":
        case "acuity-12":
        case "acuity-8":
            return acuityAnswer(rnd, input.family);
        case "counting":
            return countingAnswer(rnd);
        case "spatial":
            return spatialAnswer(rnd);
        case "chart":
            return chartAnswer(rnd);
        case "screenshot":
            return screenshotAnswer(rnd);
        default: {
            const exhaustive = input.family;
            throw new Error(`computeFixtureAnswer: unknown family ${String(exhaustive)}`);
        }
    }
}


function escXml(s) {
    return s.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
}
const EYE_CHART_GUTTER_X = 70;
const EYE_CHART_GROUP_X = [380, 683, 986];
function renderAcuitySvg(answer) {
    let baseline = 96;
    let body = "";
    for (let r = 0; r < EYE_CHART_ROW_SIZES.length; r += 1) {
        const size = EYE_CHART_ROW_SIZES[r];
        const spacing = (size * 0.14).toFixed(2);
        body += `<text x="${EYE_CHART_GUTTER_X}" y="${baseline}" font-family="DejaVu Sans, sans-serif" font-size="22" fill="#64748b">${r + 1}</text>`;
        for (let g = 0; g < 3; g += 1) {
            body += `<text x="${EYE_CHART_GROUP_X[g]}" y="${baseline}" font-family="DejaVu Sans, sans-serif" font-size="${size}" font-weight="700" letter-spacing="${spacing}" fill="#111827">${escXml(answer.rows[r][g])}</text>`;
        }
        if (r < EYE_CHART_ROW_SIZES.length - 1) {
            baseline += Math.round(size * 1.15) + 46;
        }
    }
    const frame = `<rect x="2" y="2" width="1362" height="764" fill="none" stroke="#e2e8f0" stroke-width="2"/>`;
    return svgDocument(1366, 768, frame + body, "#ffffff");
}
function renderCountingSvg(answer) {
    const body = answer.items.map((item) => shapeSvg(item.shape, item.x, item.y, item.color, 55)).join("");
    return svgDocument(1200, 900, body);
}
function renderSpatialSvg(answer) {
    let body = "";
    for (let row = 0; row < 5; row += 1) {
        for (let col = 0; col < 5; col += 1) {
            const cell = answer.cells[row * 5 + col];
            const x = 120 + col * 235;
            const y = 120 + row * 235;
            body += `<rect x="${x - 100}" y="${y - 100}" width="200" height="200" rx="4" fill="#ffffff" stroke="#cbd5e1" stroke-width="4"/>${shapeSvg(cell.shape, x, y, cell.color, 62)}`;
        }
    }
    return svgDocument(1200, 1200, body);
}
const CHART_L = 150;
const CHART_R = 1140;
const CHART_T = 120;
const CHART_B = 660;
const CHART_BAR_WIDTH = 78;
function renderChartSvg(answer) {
    const n = MONTHS.length;
    const gap = (CHART_R - CHART_L - n * CHART_BAR_WIDTH) / (n + 1);
    const pxPerUnit = (CHART_B - CHART_T) / answer.yMax;
    let body = "";
    for (let t = 0; t <= answer.yMax; t += answer.yTick) {
        const y = CHART_B - t * pxPerUnit;
        body +=
            t === 0
                ? `<path d="M${CHART_L} ${y}H${CHART_R}" stroke="#334155" stroke-width="3"/>`
                : `<path d="M${CHART_L} ${y}H${CHART_R}" stroke="#e2e8f0" stroke-width="1.5"/>`;
        body += `<path d="M${CHART_L - 8} ${y}H${CHART_L}" stroke="#334155" stroke-width="1.5"/>`;
        body += `<text x="${CHART_L - 16}" y="${(y + 7).toFixed(2)}" text-anchor="end" font-family="DejaVu Sans, sans-serif" font-size="24" fill="#334155">${t}</text>`;
    }
    for (let i = 0; i < n; i += 1) {
        const x = CHART_L + gap * (i + 1) + CHART_BAR_WIDTH * i;
        const barHeight = answer.values[i] * pxPerUnit;
        const y = CHART_B - barHeight;
        body += `<rect x="${x.toFixed(2)}" y="${y.toFixed(2)}" width="${CHART_BAR_WIDTH}" height="${barHeight.toFixed(2)}" fill="#5b8def"/>`;
        body += `<text x="${(x + CHART_BAR_WIDTH / 2).toFixed(2)}" y="${CHART_B + 34}" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="22" fill="#334155">${escXml(MONTHS[i])}</text>`;
    }
    const midY = (CHART_T + CHART_B) / 2;
    body += `<text x="50" y="${midY}" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="20" fill="#64748b" transform="rotate(-90 50 ${midY})">${escXml(answer.yAxisLabel)}</text>`;
    body += `<text x="${CHART_L}" y="60" font-family="DejaVu Sans, sans-serif" font-size="34" font-weight="700" fill="#111827">${escXml(answer.title)}</text>`;
    body += `<text x="${CHART_L}" y="90" font-family="DejaVu Sans, sans-serif" font-size="20" fill="#64748b">${escXml(answer.subtitle)}</text>`;
    return svgDocument(1200, 800, body, "#ffffff");
}
function renderScreenshotSvg(answer) {
    const rowsY = 240;
    const rowHeight = 90;
    const unitX = 1030;
    const lineTotalX = 1320;
    let rows = "";
    answer.items.forEach((item, index) => {
        const y = rowsY + index * rowHeight;
        const lineTotal = (item.qty * item.price).toFixed(2);
        rows += `<text x="80" y="${y}" font-family="DejaVu Sans, sans-serif" font-size="32" fill="#1f2937">${escXml(item.name)}</text>`;
        rows += `<text x="900" y="${y}" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="32" fill="#1f2937">x${item.qty}</text>`;
        rows += `<text x="${unitX}" y="${y}" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="32" fill="#1f2937">$${item.price.toFixed(2)}</text>`;
        rows += `<text x="${lineTotalX}" y="${y}" text-anchor="end" font-family="DejaVu Sans, sans-serif" font-size="32" fill="#1f2937">$${lineTotal}</text>`;
    });
    const dividerY = rowsY + answer.items.length * rowHeight - 40;
    const totalY = dividerY + 70;
    const body = `
    <rect x="40" y="40" width="1320" height="920" rx="16" fill="#ffffff" stroke="#cbd5e1" stroke-width="3"/>
    <text x="80" y="120" font-family="DejaVu Sans, sans-serif" font-size="40" font-weight="700" fill="#111827">AboStore - Cart</text>
    <path d="M80 155H1320" stroke="#e2e8f0" stroke-width="2"/>
    <text x="80" y="185" font-family="DejaVu Sans, sans-serif" font-size="26" fill="#64748b">Item</text>
    <text x="900" y="185" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="26" fill="#64748b">Qty</text>
    <text x="${unitX}" y="185" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="26" fill="#64748b">Unit</text>
    <text x="${lineTotalX}" y="185" text-anchor="end" font-family="DejaVu Sans, sans-serif" font-size="26" fill="#64748b">Line Total</text>
    ${rows}
    <path d="M80 ${dividerY}H1320" stroke="#334155" stroke-width="3"/>
    <text x="80" y="${totalY}" font-family="DejaVu Sans, sans-serif" font-size="36" font-weight="700" fill="#111827">Total</text>
    <text x="${lineTotalX}" y="${totalY}" text-anchor="end" font-family="DejaVu Sans, sans-serif" font-size="36" font-weight="700" fill="#111827">${answer.expectedAnswer}</text>
  `;
    return svgDocument(1400, 1000, body, "#f1f5f9");
}


  const rnd = createRng(BigInt(a.seed));
  const answer = acuityAnswer(rnd, "acuity-8");
  const svg = renderAcuitySvg(answer);
  const promptLines = [`Look at the image at {{image}} (fetch it and view it).`, answer.prompt];
  promptLines.push("Answer with just the 5-character code, e.g. AB3XZ.");
  const prompt = promptLines.join("\n");
  const expected = answer.expectedAnswer;
  return { prompt: prompt, expected: expected, images: [{ svg: svg, width: answer.width, height: answer.height }] };
})

evaluate

(function (a) {
  function normalizeWord(s) {
    return String(s).trim().replace(/^["'.]+|["'.]+$/g, "").trim().toLowerCase();
  }
  const ok = normalizeWord(a.submission) === normalizeWord(String(a.expected));
  return { pass: ok, score: ok ? 1 : 0, detail: ok ? undefined : ("expected " + String(a.expected) + ", got \"" + a.submission + "\"") };
})

submissions (3)