All the rules. All the workings. None of the fine-print surprises.
THE BASICS
Welcome to the counter
Gramps is a daily three-digit numbers game concept for Robinhood Chain, inspired by the newspaper numbers games of 1920s Harlem.
Pick a number from 000 to 999, choose a stock book, and select Straight or Box. The proposed price is 1 USDG per ticket. Every book has its own number and prize pool.
This site is an interactive product demo, not a live gambling service. No wallet is connected, no real funds are accepted, and no contracts or oracle feeds are called.
Start with Play. Your browser gets 20 free demo credits.
The last three digits of a stock’s closing price, expressed in cents, become its winning number.
For example, a closing price of $412.87 is 41,287 cents. Keep the last three digits: 287. A close of $410.07 becomes 007 — leading zeros matter.
The four books are TSLA, NVDA, SPY, and GME. Each uses its own closing price. Prices are handled as integer cents to avoid floating-point rounding surprises.
The production concept uses Chainlink to deliver prices on-chain. Feed availability, the official close timestamp, stale-price handling, and fallback behavior still need to be specified and verified before launch.
A published price makes the source inspectable. It does not make the digits uniformly random or guarantee contract security.
PLAYING THE GAME
Straight or Box?
Same three digits. Two different ways to match.
Straight requires the exact order. A Straight ticket for 287 wins only when the drawn number is 287. Winning Straight tickets divide the 70% Straight allocation.
Box accepts any order of the same digits. A Box ticket for 287 matches 287, 278, 827, 872, 728, or 782. Winning Box tickets divide the 20% Box allocation.
Repeated digits reduce the number of arrangements. 112 has three: 112, 121, and 211. 777 has only one. Repeated digits are counted, not discarded.
A ticket belongs to exactly one category. A Box ticket that happens to match the exact order still receives only its Box share.
More tickets can share a winning number. There is no fixed or guaranteed payout per winning ticket.
PLAYING THE GAME
The pool and the split
The proposed split is 70% Straight, 20% Box, and 10% fee.
Every book has a separate pool. The amount allocated to a category is shared equally among its winning tickets, not among unique players.
The concept says that when nobody wins, the pool rolls over to the next day. Exact treatment of an empty category when the other category has winners, fee timing, dust, and rounding must be defined in the production specification.
The demo uses fully disclosed fixture tickets, not real participants. See the demo section for the exact pool model and rounding rules.
Do not interpret demo pool sizes as real liquidity or demo returns as earnings.
PLAYING THE GAME
When the bell rings
The regular-session concept draws at the 4:00 PM Eastern Time market close on NYSE trading weekdays.
There is no regular draw on weekends or NYSE holidays. Eastern Time is America/New_York, so it follows daylight saving time rather than a fixed UTC offset.
The site’s calendar widget supports the 2026 NYSE full-day holiday calendar. November 27 and December 24 are treated as early-close exceptions, not as ordinary 4 PM draws. Production handling of shortened sessions and order cutoffs is not finalized.
Outside the supported year the widget explicitly reports that the calendar is unavailable instead of guessing a countdown. Emergency closures and exchange schedule changes are not reflected automatically.
The demo bell is independent of the real market clock. You can run it at any time after printing a ticket.
The countdown is an informational calendar widget, not evidence that a contract or live draw is running.
USDG is the proposed currency for tickets and prizes. No separate GRAMPS token is being announced here.
The product concept prices a ticket at 1 USDG. This preview substitutes simulated credits with no financial value. They cannot be deposited, transferred, redeemed, or withdrawn.
Production still requires a verified USDG contract on the target network, supported wallet and chain configuration, payment approvals, and tested payout behavior.
Stablecoins can carry issuer, redemption, liquidity, depegging, and network risks. The use of a stablecoin does not remove the risks of wagering or guarantee price stability.
There is no token sale, tokenomics schedule, airdrop promise, or investment offer on this site.
UNDER THE HOOD
The on-chain ambition
Robinhood Chain is the intended network and Chainlink is the proposed price-oracle source. Neither integration is active in this preview.
Before real play is possible, the project needs deployed and reviewed contracts, verified network support, suitable closing-price feeds, clear settlement and rollover rules, and a legal and compliance review.
Public settlement can make rules and results inspectable. It is not a promise that nobody can influence an underlying market price or that software is free of vulnerabilities.
There are no fabricated transaction hashes, audit badges, wallet connections, or live oracle claims in this demo.
Concept preview. Not audited, not a live contract, and not ready to accept real funds.
UNDER THE HOOD
Exactly how this demo works
A transparent practice game with predetermined numbers and simulated opponents. You can inspect the entire model.
Each new browser starts with 20 demo USDG. Every ticket costs 1 demo USDG. Progress is stored locally in this browser; Reset clears tickets and draw history and restores the initial balance. If storage is blocked, progress lasts only for the current session.
Every round and every book starts with 2,000 fixture tickets: one Straight ticket for each number 000–999 and one Box ticket for each number 000–999. Each contributes 1 demo USDG. Your tickets add to that book’s pool. These are model fixtures, not real players.
Round 1 uses TSLA $412.87 → 287; NVDA $178.43 → 843; SPY $648.09 → 809; GME $23.56 → 356. Each subsequent round adds 137 cents to that book’s sample closing price. The sequence is intentionally predictable for testing, not random or fetched from a market.
The demo divides 70% of each pool among matching Straight tickets and 20% among matching Box tickets, including fixture tickets. Each payout is rounded down to two decimals; dust stays unallocated. The 10% fee is illustrative and is not collected by anyone.
Because fixtures contain every number, both categories always have a winning fixture ticket. This demo therefore does not exercise a no-winner rollover scenario. A maximum of 100 open user tickets is allowed. The latest 30 rounds are retained in the results archive.
Try TSLA 287 Straight in round 1, print a ticket, then ring the demo bell to verify a winning outcome.
THE FINE PRINT
Keep it a game
For adults 18+ only. Real-money play, if launched, may require a higher age and may be restricted or prohibited where you live.
No strategy, number, mascot, or past result guarantees a win. Stock-price digits are not guaranteed to be equally likely. This site is not financial advice.
Never play with money you cannot afford to lose, borrow to play, or chase losses. Take breaks and set limits. This demo contains no real-money transactions.
If gambling stops feeling like entertainment, consider seeking support through a qualified local service. In the United States, the National Council on Problem Gambling provides support information at ncpgambling.org.