The fun part is that I have three sea shells mounted on a plaque just above my bathroom door.
Altho there is no true answer, my totally WAG is that they control various water jets for cleaning your ass. I did see a toilet with two controls for this, so three isnt a stretch.
I wondered if it was related to an old joke about an automated toilet system with 3 buttons.
I love the SDMB! There is NO topic we will shy from!
Oi! Thanks for reviving that memory for me! 
SIGENE posted this in a thread titled “In the dustbin of our cultural history.”
Jokes that no longer work…relegated to the dustbin in their own right.
Cashier: Do you collect stamps?
Customer: No, I build model airplanes.
The joke has to do with trading stamps. The cashier wants to know if the customer wants their trading stamps from their purchase. The customer is thinking the question is about their hobbies - like collecting stamps from the post office.
Sam and Dianne are attempting to fool the rest of the bar, so Dianne agrees to lock herself in Sam’s office. Before entering, Sam asks her “S’aright?” She replies “S’aright,” and Sam shuts the door.
That’s a reference to Señor Wences, a Spanish ventriloquist who would talk to somebody in his box after he opened it, then before closing it would ask “S’aright?” The voice in the box would reply “S’aright” before Wences shut the box.
To elaborate, it was a disembodied head in a box. Sr. Wences was one of the most surreal acts ever. I loved him when he came on Ed. Sullivan.
“Easy for you, for me ees very deefeecult!”
One more on this topic, from 30 years ago:
What do you call a Sandinista with a 976 number?
A PARTY LINER!
You had to put dimes in them. 
Are you serious? Many of my doctors still mail them out as reminders of appointments. Same with insurance companies.
Pennsylvania license plates in the late 1950’s had “PA” on them, predating the postal abbreviation.
And my veterinarian.
Sometimes I mail a postcard myself.
PA was a traditional abbreviation for Pennsylvania long before the postal codes were introduced, which is probably why it was selected instead of PE. But longer abbreviations also were used.
I get plenty of postcards from doctors and insurance companies and places offering me 10% off on my next purchase- but it’s been over 30 years since I got a postcard from a friend or relative. It’s been a similarly long time since I got a letter ( other than a Christmas letter) from a friend or relative. Email and text or other messages have replaced them.
There was an absolutely hysterical Beverly Hillbillies/ Petticoat Junction crossover story arc in which Jed Clampett is negotiating some sort of deal regarding a rural airfield with a local Hooverville character named Howard Hewes, and Drysdale thinks he’s the Howard Hughes .
I don’t know if that was deliberate or a typo, but I probably should add to the Obvious things about a creative work thread that I was just struck by the similarity of Hooterville, the mythical setting of Green Acres and Petticoat Junction and Hooverville, a shantytown built by people left homeless by the Great Depression.
I kind of remember that one.
Chuck Berry used the abbreviation P.A. in his 1958 song Sweet Little Sixteen.
They’re really rockin’ in Boston
In Pittsburgh, P.A.
…
Cause they’ll be rockin on bandstand
In Philadelphia P.A.