Cairn
A trail cairn of numbered granite stones. Drag a chain through stones that touch, starting with two that match, and let go to merge them into one bigger stone. The pile keeps refilling from the top, and from 2K up each new stone is named for a New Hampshire peak. Play Endless for a best score, or try today's board, the same for everyone. Your game stays on your device.
A trail cairn of numbered granite stones. Drag a chain through stones that touch, starting with two that match, and let go to merge them into one bigger stone. The pile keeps refilling from the top, and from 2K up each new stone is named for a New Hampshire peak. Play Endless for a best score, or try today's board, the same for everyone. Your game stays on your device.
| Arrows | Move around the pile |
| Space | Start a chain, or add the stone to it |
| Enter | Merge the chain |
| Backspace | Take the last stone off the chain |
| Esc | Clear the chain or put a tool down |
Press on a stone and drag through its neighbors, in any of eight directions, to draw a chain. Start with two stones that match; after that each stone must equal the one before it or be double it. The sum shows as you go. Let go and the chain merges into its last stone. Drag back over a stone to take it off the chain. With a mouse it works the same way.
- Merging
- A chain becomes one stone: the next power of two at or above its sum. 2, 2 and 4 add up to 8 and make an 8. 4, 4 and 8 make a 16. Three 2s add up to 6 and make an 8. The new stone sits where the chain ended, the rest clear, the stones above fall, and new ones drop in from the top. Your score goes up by each stone you make.
- The end of a game
- As the stones grow, the new ones that drop in grow too, and the smallest stop coming. The game ends when no two matching stones touch. You can then clear the bottom two rows and keep going, or start over.
- Tools
- The Hammer removes one stone. Swap trades the places of any two stones. Undo takes back your last move, up to five in a row. Each use counts against the same tool allowance as the hints in the other games.
- Summit stones
- From 2K up, each new stone takes the name of a New Hampshire peak, lowest first: Kearsarge, Cardigan, Monadnock, Chocorua, Carrigain, Moosilauke, Lafayette, Madison, Jefferson, Adams and, at 2M, Washington. The numbers are names, not elevations. The first time you reach each one in a game, the pile celebrates.
- Today
- Today's board and every stone that drops into it are the same for everyone on a New Hampshire date. The goal is a 1K stone in as few moves as you can. Restarting puts the same board back, and the share line says how many moves and tools it took.
About Cairn
Is Cairn free?
Yes. Cairn is free to play in your browser, with no account and nothing to download.
How do merges work?
Start a chain with two matching stones that touch, then add stones that equal the one before or double it. Let go and the chain becomes one stone: the next power of two at or above its sum.
How is it scored?
Your score goes up by the value of each stone you make. Endless keeps your best score. Today's board is scored by moves instead: reach a 1K stone in as few as you can.
When does today's board change?
A new board comes out at midnight New Hampshire time (Eastern time), and everyone gets the same one on the same date. If you have the page open at midnight, reload it to get the new one. Every stone that drops in is the same for everyone too, and restarting puts the same board back.
When does a game end?
When no two matching stones touch. You can then clear the bottom two rows and keep going, or start over. Clearing the rows, the Hammer, Swap and Undo all draw on the same allowance as hints in the other games.
Does it work on my phone?
Yes. Press a stone and drag through its neighbors in any of eight directions, then lift to merge. Your progress is saved in this browser on this device. There are no accounts, so it doesn't follow you to another device, and clearing the browser's data for the site erases it.
