I got the idea of sending her the message "Happy Belated Thirtieth Birthday!" with each character on a separate postcard, all sent via separate post offices.
So I researched 30 separate interesting towns in the US. Then I ordered 30 postcards, each with a picture of the place on the front, and a single character of the message on the back in a large block letter. Finally, I wrote a note on each that said something about the place but started with the big block letter.
Then, I mailed them all to the postmaster at each location, stamped and inside an envelope along with this letter to the postmaster: Dear Postmaster: I am mailing my sister 30 postcards from 30 towns for her 30th birthday.
I have enclosed a postcard, which I ask be hand-cancelled with a postmark from your town. To protect the postcard from machine cancels in its journey through the mail system, I have enclosed a stamped envelope addressed to my sister in which to seal and mail the postcard. Thank you very much for your time!
About a week later my sister starts getting the cards, but it doesn't make sense to her so she calls me after a few. I tell her just wait, there's more, she'll understand soon enough.
Finally after maybe 2 weeks she had all the cards and was able to decode the message.
Oh, I also found a 50-state stamp set on eBay so they all had unique stamps.
It was cool. Here's what they all looked like along after she received them with an closeup of one:
Barrow, AK and Kealakekua, HI travelled the farthest, from my home in NC to those cities to my sister in Miami, FL. There didn't seem to be much correlation between the distance the cards traveled and how soon she got them.
It would be cool to have a service (maybe one already exists?) that specializes in the processing/fulfillment of machine-unfriendly mail pieces.
Reminds me of this guide: https://thepostmansknock.com/how-to-make-deliverable-mail-ar...
Stamps are such that one must have one to mail something, so why not pick one with a pleasing aesthetic?
I'm working on a side project centered around graphic art containing varying subject matter aimed to be used in a similarly nuanced way as mail art.
I believe this idea is even more applicable in the digital world as graphics are more readily available than artistic stamps.
If you're into this, it's fascinating to check out the earlier editions of the contest and the winners. One of my long term hopes is to actually send in something which they atleast consider.