Every passenger cab carries the same object. A 6 × 9 inch bond certificate sits behind scratched glass in a heavy aluminium frame, screwed to the wall at eye height, renewed each year, posted in a conspicuous place because the code says conspicuous.

The paper is deliberately plain: black form type on white, ruled label-and-value rows, a boxed capacity table. Only two inks break the monochrome — the municipal seal in blue and the rubber-stamped expiry in red. All the material lives in the frame.