A mine with one paying face.
PITHEAD is a round-based game on Robinhood Chain. The mining face has 25 blocks. Miners deposit ETH on the blocks they choose; when the round closes one block is drawn, and everyone who deposited on it shares the round's prize.
The game is a single smart contract. It holds every deposit, performs the draw, and pays winners when they collect. There is no account, no sign-up and no off-chain balance. The $PITHEAD token is the community side of the project and is not needed to play.
One round, start to finish.
A new round opens with the operator's sealed secret already committed. It waits — at no cost to anyone — until the first miner deposits. That deposit starts a 60-second timer.
Settlement and the opening of the next round happen in the same transaction, so a busy mine moves from one round straight into the next.
Split blocks and Solo blocks.
Split (16 blocks). Any number of miners can deposit on a Split block. If it is drawn, the prize is divided in proportion to what each miner deposited on that block.
Solo (9 blocks, marked ×, laid out in an X). The first wallet to deposit on a Solo block owns it for the round — nobody else can join. If it is drawn, that wallet takes the entire prize. The owner may add more to its own Solo block.
Every block, Split or Solo, has the same 1-in-25 chance of being drawn.
One amount, divided evenly.
You enter a single total for the round. The contract divides it equally across the blocks you picked; any indivisible wei goes to the first block, so the total is exact. Minimum is 0.0001 ETH per block.
| Total | Blocks | Per block | Chance one is drawn |
|---|---|---|---|
| 0.01 ETH | 1 | 0.01 | 4% |
| 0.05 ETH | 5 | 0.01 | 20% |
| 0.10 ETH | 10 | 0.01 | 40% |
| 0.25 ETH | 25 | 0.01 | 100% |
Covering more blocks raises your chance of being on the paid block, not your expected return: with a 30% team share, the long-run expectation of every deposit is negative.
How the paying block is chosen.
Two ingredients, from two parties, neither of which can see the other in time:
commit = keccak256(seed) // locked when the round opens
entropy = blockhash(closeBlock) // produced after deposits stop
block = keccak256(seed, entropy, roundId) mod 25 + 1
The operator commits to seed before anyone deposits and cannot change it — the contract rejects any seed whose hash differs. The entropy is the hash of the block in which deposits closed; it did not exist when the round closed, so nobody could aim deposits at it. Both values are published in the Settled event, and the Verify page recomputes every draw in your browser.
Seventy to the face, thirty to keep it running.
Of each round's deposits, 70% becomes the prize and 30% is credited to the team wallet. The 30% pays for the mine itself: the keeper bot that opens and settles every round (it spends gas on each one), the servers that index rounds and serve this site, and the people building it. The share is set once when the contract is deployed and is immutable; nobody can raise it later. If nobody deposited on the drawn block, the whole prize rolls into the next round's pot, untaxed.
Anyone can also add ETH straight to the pot with fundPrize(); it goes entirely to winners.
When something goes wrong.
Operator silent. If the secret is not revealed within 30 minutes of the deadline — or before the closing block hash expires — anyone can call refund(). Every deposit becomes claimable in full and the rolled-over pot is kept for the next round.
Bot offline. No new rounds open, but nothing is stuck: collecting prizes and refunds only needs your wallet.
Forgot to collect. Prizes stay claimable for 90 days. After that, anyone may return them to the pot, where they are paid to future winners.
Setting up your wallet.
Any EVM wallet works — MetaMask, Rabby, Phantom and others. Robinhood Chain uses chain ID 4663 and ETH for gas; fees are a fraction of a cent.
Phantom: open Settings → Active Networks and turn on Robinhood Chain first. PITHEAD will then switch to it automatically when you connect.
PITHEAD will never ask for your recovery phrase. The only transactions it requests are deposit and claim on the game contract shown in the footer of the Mine page.