rules

A cairn is what walkers build by each adding one stone to a heap, so the people behind them know somebody came this way. This one is a contract on Robinhood Chain and it does exactly that and nothing else. It has no deadline, no winner, no jackpot and no way to lose what you put in it, because nothing you put in it is held anywhere — it is burned.

place() adds a stone with your address on it. You can call it once per UTC day, forever. Not a rolling twenty-four hours from your last stone — a calendar day, so everybody shares the same window and the streak means the same thing for everyone. A streak is consecutive days; miss one and it resets to one, and your best streak is kept separately on chain.

Nothing in ETH. place() is not payable — the contract cannot receive ETH, has no withdraw function and holds no balance of any kind. The cost is a fixed burn of CAIRN tokens, sent from your wallet straight to 0x…dEaD. The contract never touches them and nobody can retrieve them. Every 500 stones, the next stone costs one more unit of the base burn, so the pile gets heavier as it grows.

The shape is keccak256(your address, the stone's index), read out as width, height, lean, tone, cut and how much moss it has taken. It is fixed the moment you place it and there is no function that can change it — not the owner's, because the owner has no functions left. The contract draws it itself: stoneSvg(index) returns the picture, and cairnSvg(from, count) returns the stack. The site draws the same shapes from the same numbers so the page stays fast.

Two things, each exactly once, and both before the first stone: setFuel() wires the CAIRN token (it does not exist when the contract is deployed — it is launched on pons afterwards) and open() opens the pile. After that the owner has no callable function at all. There is no pause, no upgrade, no proxy, no admin, no fee switch.

A stone in a pile, with your address on it, that stays there as long as the chain does. That is the entire product. It does not entitle you to anything, it cannot be sold, transferred, redeemed or staked, and placing one will not make anything you hold go up. If you want a game with a prize, this is not that — the two before it were.