A Richmond, Va. man receives five postcards with strange messages and clues

https://www.wric.com/news/local-news/mystery-mail-richmond-man-receives-five-postcards-with-messages-and-clues/

There have been allsorts of bizzare and hidden_messages throughout history.

https://www.wvnstv.com/news/national-news/mystery-mail-virginia-man-receives-cryptic-postcards-from-unknown-sender/amp/

 https://www.coasttocoastam.com/article/video-virginia-man-baffled-by-series-of-cryptic-messages-mailed-to-his-home/

https://thoughtcatalog.com/january-nelson/2018/12/50-disturbing-messages-real-people-have-received-in-letters-and-texts/

https://thoughtcatalog.com/kate-bailey/2013/10/19-cryptic-text-messages-and-what-they-actually-mean/

https://en.wikipedia.org/wiki/Cicada_3301

https://www.fastcompany.com/3025785/meet-the-man-who-solved-the-mysterious-cicada-3301-puzzle

https://www.zmescience.com/other/feature-post/cicada-3301-puzzle-brightest-minds-posted-unknown-mysterious-organizationt/