Cairn is a quiet puzzle about bringing stones home.

Swipe up, down, left or right. Every loose stone on the board drifts one cell that way, all of
them at once, in the same direction. A stone cannot cross a wall, the board edge, or another
stone, so a blocked stone holds its cell and the ones behind it stay where they are.

Scattered over the board are rings. A stone that comes to rest on a ring settles there: it turns
to solid rock and is a wall for the rest of the level. Fill every ring and the level is done.

That last rule is where the puzzle lives. Every stone you bring home permanently reshapes the
board, so the order you settle them in is the real problem, not the path of any one stone.

Then the ground starts to help, and to interfere.

Wind tiles carry a stone that arrives on them along the stream, cell after cell, until the wind
runs out or something blocks the way. A stone already sitting on wind is not carried; you have
to arrive.

Ice tiles carry a stone that arrives on them onward in the direction you swiped, until the ice
runs out or something stops it. Ice has no arrow of its own. It follows your hand.

Portals come in linked pairs. A stone that arrives at one mouth comes to rest at its twin, if
the twin is free. If it is not, the stone rests where it landed. Either way it stops there.

Every stone and every ring is alike, so any stone may fill any ring. Nothing is lost by trying a
line and undoing it: no timer, no score, no stars, and unlimited undo.

It plays with one thumb, offline, a level at a time. The early ones take a minute. The later ones
take as long as they take.

WHAT IS IN IT

Journey: 828 levels across twenty-two chapters, from Pebbles to Lodestone. Walls first, then
wind, bends, ice and portals, then all of it together. Each chapter takes one idea further and
carries its own colour, so the game changes shade as you climb. Thirty-five boards are hand-made
rather than generated: one per chapter, stating that chapter's idea plainly.

Zen: 580 puzzles, ordered gently from easy to hard and never locked, with more generated in the
background as you play.

Daily: one puzzle each day, open from the first launch, the same one for everybody that day, and
a streak if you keep it up.

Forty achievements: a ledger rather than a prod. Nothing gates, rewards or interrupts.

EVERY LEVEL IS SOLVABLE, AND PAR IS PROVEN

Levels are generated and then exhaustively solved, by searching backwards from the finished board
across every arrangement the stones can take. A level therefore cannot be impossible, and its par
is the shortest solution that exists rather than an estimate. Par is there to be met or ignored.

IF YOU GET STUCK

The Journey runs in order, but it will not trap you. Leave a level unsolved three times, having
actually played it, and the game offers to set it aside: the next level opens, nothing is
recorded as solved, and the tile stays on the grid as a broken ring to come back to. A chapter
opens once two thirds of the one before it is solved. One hard puzzle never ends the climb.

MADE RATHER THAN ASSEMBLED

Every shape on screen is drawn by the game as it runs rather than loaded as a picture, down to
the grain in the paper. Every sound is synthesised at launch from one pentatonic scale, and
the settling notes climb as a level fills.

Six themes, which cross-fade rather than snap. One light source drives both
the moving backdrop and every shadow in the app.

Set Motion to still and everything that loops stops. What answers your touch carries on.

Sound and haptics each switch off. The board turns with your device, portrait or landscape.
No account and no sign-in, and the puzzles themselves need no connection.

FREE, WITH ADS

Ads pay for the game. They appear on the menus, and sometimes between levels — never while a
puzzle is on screen, and never interrupting one. A one-time purchase removes them for good.

Bring the stones home.