Each piece carries a certificate. The certificate establishes the copy rank, the total number opened, the date, the materials and the contract identifier.

The seven original works are inscribed on Polygon, ERC-721 standard, tokens 1 to 7. No eighth token will be issued on this contract. The number is fixed and does not move.

Each work was photographed in the studio at completion. The file carries its date and geographic coordinates, written by the device. These files establish creation precedence over the chain inscription, piece by piece. They are given to the buyer and to any expert appointed by them, on written request.