Drystone app icon: three courses of unevenly cut pale stone on near-black

Drystone

A number puzzle that never runs out — every board built on your phone, graded by the thinking it actually takes.

Coming soon to the App Store

£2.99 once · iOS 26.0 or later · no subscription, no account

A five-by-five Drystone board, one square selected with a warm amber outline

Fill each block with 1 to its size. No two of the same number may touch — not even diagonally.

WHY DRYSTONE

Never runs out

Puzzles are generated on your phone the moment you ask for one. No server, no download, no connection — and no end to them.

Difficulty that is honest

Graded by the hardest technique a solve actually forces, not by counting the given numbers. It is why other apps hand you an "expert" that plays like a warm-up.

Completely private

The app makes no network requests at all. There is no account, no sign-in, no analytics, and nothing to collect.

HOW IT WORKS

Suguru is two rules. Every block holds the numbers 1 up to however many squares it has, and no two identical numbers may touch — including diagonally. That second rule is the whole game: it is what turns a small grid into something worth thinking about.

Drystone builds each puzzle on your device and then checks it the way a person would, so a board labelled Expert is one that genuinely forces an expert technique — not one that simply hid more numbers. Nothing is fetched, so they never run out and they work on a plane.

IN THE APP

Ask for a hint and it shows you the next logical step and the reasoning behind it, never just the answer. Pencil marks sweep themselves as you place numbers, and undo is lossless all the way back.

One daily puzzle is shared by everyone, derived from the date itself. It warms up on Monday and bites by Sunday, it keeps a streak, and it stays free whether or not you ever buy anything.

Drystone showing a hint: one square ringed in amber with the technique explained beneath the board

WHAT IT COSTS

Drystone's record screen: puzzles solved, current streak, best run and best flow

One payment, and that is the whole business model. Easy and Medium are free to play, and so is the daily. £2.99 unlocks Hard and Expert, unlimited puzzles and the hint engine.

No adverts on either side of that line. No subscription. No account, no sign-in, no email address. It unlocks on every device signed in to your Apple Account, and it is shareable with your family.

Simple rules. Endless moves.

£2.99 once, on iOS 26.0 or later.

Coming soon to the App Store