You know what I’m talking about. When a ransomed sends a ransom note spelled out in various fronts clipped out of various magazines. What was the first appearance of that? Was it a movie? In which case, mods, please move this to cafe. Or was there a real case that this trope was based on? What is this technique even called? Thanks for any helpful leads, or search terms.
Unless there’s a pandemic of these notes 
I think this was meant for General Questions.
Ah crap. I blame severely multitasked phone resources (I’m in video chat as I type) and beers. Yes, totally meant for GQ.
This article attributes it to fiction, specifically Arthur Conan Doyle’s Hound of the Baskervilles, where the cut-out note was a warning rather than a ransom demand. This wiki entrysays it’s HOTB as well.
Excellent. Thank you.
What keywords did you use to search, if I might ask?
first clipped ransom note
That’s so easy, I never would’ve gotten there. 
nm
mOvEd
Aha! This looks like the work of…
The Masked Moderator!
It’s still really hard to find the word “moor” to clip out of a newspaper or magazine. 
FWIW, I tried this once in college, (as a joke, I was ransoming someone’s pillow IIRC) and it takes a LONG time to find all the letters you need. I had a stack of Rolling Stone & Time magazines, and I spent over an hour to put a 3 sentence note together. Eventually I gave up and started writing in some of the letters.
Well, my question is, what would the modern way to do this be?
I know the reasoning to do this is because typewriters have flaws which could be match up similar to gun ballistics, and obviously handwriting could be recognized. And doing it on a computer could leave evidence on the computer.
So how would you make an untraceable note today? (we’ll assume fingerprints were avoided).
You’d do it on a computer. The evidence on the computer would be on your computer, which wouldn’t be found until after they found you in some other way.
It always bothered me that Beryl was just too hurried or lazy to just cut out “mo” and “or” from the paper, or even the letters “m” “o” and “r” and paste them into place. There was time to search through to find the rest of the words to make up the note, but not those, evidently.
Even better, do it on a public computer and printer, like at a library or quick-print place.
Watch out for microdots:
I’d also try to use something other than a Microsoft Office product and I’d still probably rearrange the letters of the message so searching the seized PC wouldn’t return phrase match results. Then print, cut & paste.
Why even print it? Send it electronically.
Sending it electronically can leave even more traces. If it’s send via email, the recipient will be able to see which email servers the message passed through, possibly some information about the sending computer, and even the IP address of the sender. A knowledgable sender can hide some of this but not all of it.