A new canvas is painted every day, but only today's is mintable. Every earlier day already exists on Base and is sitting behind a marketplace detour. These are the days you can collect right now — cheapest first, bought without leaving the app.
Prices are live Seaport listings from OpenSea. Before the wallet prompt the app re-checks the chain, the exact day, the collection contract, the Seaport target, the quantity and a hard price cap. Open source: basepaint-archive.