Open Letters is a trading card set of inventions filed with the U.S. Patent office.

Each pack contains 10 cards depicting inventions randomly chosen from our curated selection.

On the front of the card is an image of the invention, along with the inventor’s name. On the back is more information including filing date, prior art, citations and a short description. The card's rarity is calculated according to a set of parameters and is noted on the card.

The name Open Letters is derived from its Latin origin “litterae patentes”. Unlike sealed letters intended for a single recipient, literae patentes were meant for public disclosure: to be read and understood by all. This openness is the foundation of the patent system - a mutually beneficial exchange between inventors and society.

In the spirit of literae patentes, this pocket-sized archive is more than a stack of legal documents. Open Letters is a testament to human ingenuity and also a call to engagement, intended as a tangible expression of transparency, collaboration and the power of publicly accessible knowledge.

This project is for education and collectible purposes only. Patent data is sourced from public records and may be edited for clarity or design. All trademarks, logos and names remain the property of their respective holders. No affiliation with the USPTO, WIPO or any patent holder is implied.

Pen Type-C

Pen Type-C

Studio Sketchbook

Studio Sketchbook

Open Letters

Silo

15mm Titanium Insert

Pocket Field

Pocket Fiche