I write a lot of letters. About two years ago I began making letters that are difficult to open. Some are difficult to open without damaging the letter inside (ex: sewn trhough repeatedly with a sewing machine), some are so elaborately and painstakingly packaged that they make the recipient hesitate before opening (ex: packaged in a crocheted envelope), and some difficult to reconstruct (ex: written on 40 unnumbered small pieces of paper folded into modular origami shapes).

Does anyone else in this group have postal projects of this ilk?