An onchain billboard on Base

Canvas64 is a billboard whose rules live in a contract, not on a server. 64 cells, each claimed for $30 in USDC on Base and then open to a buyout by anyone at 1.65× the last price. The contract takes the buyer's USDC and pays the owner who is bought out, every earlier owner's royalty and the 2% fee, all in the sale's own transaction.

What the contract enforces

• The price of every step: $30 × 1.65^(n−1), so $30, $50, $82, $135 and on, with no cap. A buyer names the step they pay for, so a buyer who loses a race is never charged.
• The payout: the owner who is bought out gets the new price less the royalties and the fee, $49 for a cell claimed for $30.
• The royalties: owner k earns 5% × 0.75^(k−1) of every later sale of that cell, all together under 20%.
• Ownership: a cell belongs to the wallet that bought it until the next buyout. Nobody can take it any other way.

The contract is 0x99Ff41906550F0C0F3EC66a11525e38C548e5011 (chain 8453). Its source is verified and public, it has no upgrade, and every owner, sale and payment can be read from the chain: the rules.

What the team can and cannot do

The team can stop new sales for an emergency, seven days at a time, publicly and lapsing by itself, and can move the platform's own share to a new address. It cannot change a price, a rate or an owner, take a cell or touch anyone's money. The audit status and the rest are on trust and safety.

What a cell shows

The owner's photo or avatar, name and links to Twitch, YouTube, Kick, TikTok, Instagram, X or Linktree, set from the same wallet and changed at any time for free. The three priciest cells are shown again on the boards above the wall.

Read it from code

Everything the wall shows is one call away, with no key: a public JSON API, an MCP server for AI agents that can also prepare a purchase for the buyer's own wallet, and the contract itself (cells(), priceAt(step), ownersOf(cell)).

Claim a cell

You need USDC on Base and a little ETH there for the network fee (wallets and paying). Open the wall, pick a free cell and claim it: an approval of exactly $30, then the purchase. Read Before you buy first.

This page as Markdown: onchain-billboard.md. All of the docs in one file: llms-full.txt.