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A quiet planning game

Cairn.

See the whole path
before you move.

Build the goal shown above the posts,
one stone at a time, in as few moves as you can.

  1. 1
    Read the goal

    The cairn above the posts shows where each stone belongs.

  2. 2
    Plan, then move

    Lift a top stone, drop it on another post. Posts fill up.

  3. 3
    Find the optimal path

    The fewest moves. Try Hanoi rules for a classic twist.

Run best0
How to play
RUN · 3 STONES · OPTIMAL 2BEST 0
Score0
Level1
Lives
Solve it optimally to level up
Build thisOPTIMAL 2
Plan the whole path before the first move.
3 lives · no clock · think first

Find the optimal path.

Build the goal shown above the posts in the fewest moves. Lift a stone, then tap or drag it onto another post.

An optimal cairn scores 20 here, plus a streak bonus up to 4×. Over optimal scores half.

A small reset for your mind.Tap or drag stones · 1 2 3 to pick posts · Esc to pause
SEE IT BEFORE YOU STACK IT

Plan the cairn.

The cairn above the posts, under Build this, is the goal. Restack your stones to match it, post by post. Only a post’s top stone can move, one at a time, and each post holds only as many stones as it is tall.

Every cairn has an optimal solution: the fewest moves that solve it, found by searching every possible arrangement. Your efficiency is the optimal moves divided by the moves you made. It’s the Tower of London task, a classic test of planning: work out the whole sequence first, especially the moves that take a stone out of the way, then play it.

Moving
Tap a post to lift its top stone, then tap the post to drop it on. Or drag it there. Tapping its own post puts it back for free; only drops on another post count as moves. Keys 1, 2 and 3 work too.
Hanoi rules
Switch on Hanoi rules for the Tower of Hanoi twist: stones come in sizes, every post holds them all, and a stone may never sit on a smaller one.
Easy to Harder
Pick a difficulty to play single cairns at your own pace: no lives, no score, a clock for your best optimal time. Start over, or watch the optimal path, whenever you like.
The run
Solving optimally goes up a level: one more optimal move, and later a fourth and fifth stone. Your first move past optimal costs one of 3 lives, and the next cairn steps a level down. An optimal cairn scores 10 per optimal move, plus a streak bonus up to 4×. A stone glows when it sits where the goal wants it.