These letterpress-printed lick-and-stick perforated stamps aren't actual US postage, but rather a series of artist-created stamps that you can stick on letters, notebooks and more. Flower Field on Navy was created by Portland artist/illustrator Lisa Congdon. 

The Portland Stamp Company makes stamps the old-fashioned way: on dry-gum backed paper with a 100% foot-powered Rosback perforator. They use a variety of printing methods, including risograph, letterpress, and digital.