The mechanism
There is no oracle to trust here and no admin who calls the result. The price lives in a pool on this chain, the contract reads it, and anyone can recompute the same answer from the same public data.
Higher at the close than at the open is up. Both ends are averages, not instants, and that is the whole defence.
A single price settles on one instant, and one instant is cheap to buy. The shallowest market here holds around a quarter of a million dollars — enough that someone could shove the price through it for the length of one block and put it straight back, deciding the day for the cost of the spread. The markets page shows what each pool actually holds, read live rather than written down here.
Against a time-weighted average that stops working. To move the settlement you have to hold the price away from the wider market for a real share of half an hour, paying arbitrageurs on every block you hold it — and then do it again at the other end of the day, in the same direction, without anyone taking the free money in between.
The pools are Uniswap v3-shaped but were deployed without the observation
array, so observe() reverts and there is no built-in average to read. The
contract keeps the same accumulator outside the pool instead: anyone may call
poke(), which credits the last observed price for the time it actually stood.
A price that appears and vanishes between two pokes is credited no time at all.
The pot is the token's own trading fees. Picking is free — you pay gas and nothing else — and that is deliberate rather than generous: a player who stakes nothing is entering a contest with a prize, not making a wager on a security.
There is no entry fee, and no function to add one.
Everyone who calls it right splits that day's pot. If nobody does, it stays where it is and tomorrow is worth more.
A holding requirement, checked when you pick and again when you claim. One stack of tokens walked between a hundred wallets fails the second check, so a hundred entries need a hundred stacks held at the same time.
It is a blunt tool. It does not stop someone genuinely wealthy from entering many times — it only makes it cost what it should.
Every design has edges. These are the ones worth knowing before you play, and they are on this page rather than buried because finding them yourself later is worse.