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Draw a box around anything you don’t understand.

The chart, the formula, the dense paragraph, the scanned page. Explain It answers in a small card right beside it, so you keep reading instead of opening another tab.

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a-field-guide-to-patterns.example / sunflowers
A field guide to patternsChapter 3

The angle a sunflower keeps

Count the spirals on a sunflower head and you will almost always land on two neighbouring Fibonacci numbers: 34 curling one way and 55 the other, or 55 and 89 on a big bloom. The plant isn’t counting. It is repeating one turn, over and over.

θ = 360° ⁄ φ² ≈ 137.5°

Because φ is the number that fractions approximate worst, no seed ever settles directly behind an earlier one. Nearly any other angle leaves spokes and empty wedges. This one fills the disc evenly, which is how a head fits the most seeds.

Fig. 3 340 seeds, each turned 137.5° from the last.
Drag over anything on this page
Box or select any part: one sentence, two neighbouring ones, half the formula, the middle of the spiral. The answer covers what you picked and nothing around it. Then try the side-panel button in the card’s corner. Answers in this demo were written ahead of time.
How it goes

One question, without losing your place.

1

You’re reading along. Then a chart stops you cold.

Every article, paper and report has one: the figure everyone else seems to get. Usually that’s where you start skimming.

2

Draw a box around it.

Click the icon or press Alt Shift E, then drag over whatever lost you. Or just select some text and pick Explain it.

3

The answer appears right next to it.

In plain words, in a small card on the page. The thing you asked about stays in view.

4

Then ask “why?”

Not quite there? Ask a follow-up in the same card. It remembers what you pointed at.

5

Keep it open while you read on.

Move the conversation to the side panel and carry on scrolling. Your explanation comes with you.

Works on

If it’s on your screen, you can ask about it.

Draw the box around the whole thing: the chart with its axes, the full formula, the entire menu. The answer is about what’s inside the box.

A chart
The line is an estimate, and the shaded band around it shows how unsure it is. The band gets wider to the right, so the estimate is less certain there.
A formula
Add a half, then a quarter, then an eighth, forever. The total creeps toward 1 but never goes past it.
A snippet of code
It removes duplicate tags, keeping the first time each one appears, then passes the cleaned-up list to render to show it.
A menu abroad
A set menu: three courses for 28 euros. Pumpkin soup to start, then duck confit, and tarte Tatin, an upside-down caramelised apple tart, for dessert.
A map
These are contour lines: each one joins points at the same height. The small rings on the right mark a hilltop, and the lines bunch up around it because the slope there is steep.
A diagram
A 9-volt battery pushes current through a 2Ω and a 3Ω resistor in a row. Together they make 5Ω, so 9 ÷ 5 = 1.8 amps flows around the loop.

Stop skimming past the hard parts.

Add Explain It to Chrome. Next time something stops you, it’s three keys away.

Alt+Shift+E
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