How to play.
The notebook
Each page of the notebook shows eight specimens from one subject: the planets, the trees of the forest or the birds of Europe. Their names are hidden in the grid of letters. Drag across a name, or tap its first letter and then its last. When you find one, its drawing is inked in, the colours go on, and you read one short fact about it, with a link to the page the fact comes from.
A finished page becomes a small poster you can keep: download it as a picture that prints on A4, or copy a short note about it.
Today and endless pages
Today's page is the same for everyone and changes at midnight where you are. Monday and Tuesday are gentle (names run across, down and diagonally down), Wednesday and Thursday are steady (all four forward directions), and Friday to Sunday names run every way, backwards too.
The endless pages go on for as long as you like. Every page has a new grid, the subjects take turns, and the first pages are the gentle ones. Nothing is lost if you stop: your place is kept.
Controls and hints
Keyboard: Tab into the grid, arrows move, Enter or Space marks the first letter and then the last, Escape clears, H asks for a hint. Tap a specimen to read its fact again.
Hint first circles the first letter of a name you have not found yet. Press it again and a dashed line shows the whole name, which you still trace yourself. Hints are free and have no limit. There is no timer and no score to beat.
Sound is off until you turn it on.
About this game.
Every grid is generated in your browser from the date or the page number, by our own program, and the program checks it before you see it: every name is in the grid exactly once, and no rude words turn up among the filler letters. The drawings are ours, drawn in code line by line, with no photographs and no AI generated images.
Each fact is a sentence we wrote from a page we read, and that page is linked next to the fact and listed below. Your progress stays only in this browser. Our anonymous statistics (self hosted Umami) count the page visit and a few events: that a page was started or finished and in how many seconds, and that a hint, the download or the note was used. Nothing else.
This is an early version. If something is missing or in the way, write to support@arling.sk.
Sources.
Every fact in the notebook and the page it comes from. All pages were read on 26 September 2026.
The Solar System
- The Sun. The Sun holds about 99.86% of all the mass in the Solar System. Wikipedia: Sun
- Mercury. Mercury is the smallest planet and the closest to the Sun; one lap takes about 88 Earth days. Wikipedia: Mercury
- Venus. Venus is the hottest planet, and it spins the opposite way to most planets, Earth included. Wikipedia: Venus
- Earth. Earth is the only world known to harbour life, and its ocean covers about 71% of the crust. Wikipedia: Earth
- The Moon. The Moon always turns the same side to Earth, from an average distance of about 384,400 km. Wikipedia: Moon
- Mars. Mars looks red because its surface is rich in iron oxide. Wikipedia: Mars
- Jupiter. Jupiter has nearly 2.5 times the mass of all the other planets put together. Wikipedia: Jupiter
- Saturn. Saturn is the only planet less dense than water, and its rings are mostly water ice. Wikipedia: Saturn
- Uranus. Uranus was the first planet found with the help of a telescope, by William Herschel in 1781. Wikipedia: Uranus
- Neptune. Neptune has the strongest winds of any planet, up to about 2,100 km/h. Wikipedia: Neptune
Trees of the Forest
- Oak. An oak's fruit is a nut called an acorn, which sits in a little cup. Wikipedia: Oak
- Birch. Birch bark often peels in thin papery plates; it was used for canoes and for ancient books in India. Wikipedia: Birch
- Beech. Young beeches and clipped beech hedges often keep their dead leaves all winter, until spring. Wikipedia: Fagus sylvatica
- Pine. A pine in California known as Methuselah is around 4,800 years old. Wikipedia: Pine
- Willow. Almost all willows take root readily, even from broken branches lying on the ground. Wikipedia: Willow
- Maple. Maple seeds come in winged pairs, shaped to spin as they fall and ride the wind. Wikipedia: Maple
- Sweet chestnut. Sweet chestnuts grow three to seven at a time inside a spiny case. Wikipedia: Castanea sativa
- Ash. Ash wood is tough and hard to split, the classic wood for tool handles and hurling sticks. Wikipedia: Fraxinus excelsior
- Yew. Every part of the yew is poisonous except the red flesh around the seed. Wikipedia: Taxus baccata
- Holly. Only female holly trees bear berries, and they need a male tree nearby. Wikipedia: Ilex aquifolium
Birds of Europe
- Robin. Both male and female robins sing all year round, even in winter. Wikipedia: European robin
- Wren. Weight for weight, the tiny wren sings ten times louder than a cockerel. Wikipedia: Eurasian wren
- Magpie. Magpies can recognise themselves in a mirror, something only a few species are known to do. Wikipedia: Eurasian magpie
- Grey heron. A grey heron can stand motionless in the shallows, waiting for a fish to come within reach. Wikipedia: Grey heron
- Barn swallow. Barn swallows build their cup nests from pellets of mud carried in their beaks. Wikipedia: Barn swallow
- Kingfisher. A kingfisher dives with its eyes open, shielded by a clear third eyelid. Wikipedia: Common kingfisher
- Barn owl. A barn owl hears so precisely that it does not need sight to hunt. Wikipedia: Western barn owl
- White stork. An adult white stork's main sound is the clatter of its bill; its voice is only a faint hiss. Wikipedia: White stork
- Puffin. A puffin can catch several small fish in one dive, holding the first ones with its tongue. Wikipedia: Atlantic puffin
- Goldfinch. Goldfinches use their tweezer-like bills to pull seeds out of thistles and teasels. Wikipedia: European goldfinch