Not especially relevant, and I’ve said it before in a different context.
When programmers add comments to code, we think we’re doing something new and modern. Here’s a piece of my C++ code from Audin, my all-purpose courseware engine. The active parts are on the left, and my explanations and reminders are on the right. The editor’s built-in colorizer makes the keywords (if, else, case, break) red, and the variables black.
As I peruse medieval history, I’m noticing that the scribes used the same technique to divide the red action parts from the black description parts. In this document the REMS are on the left, but they were sometimes the other way. [For clarity, I’m NOT reading the documents themselves! I can halfway read Middle English and Latin in print, but I can’t begin to decipher the script. Leave that to the experts.]
I designed my courseware in medieval form without knowing it. I started using this pattern in 1998 and continued it through many versions and platforms. Text on the right, illustrations or diagrams on the left.
Books and documents since the Endarkenment mostly abandoned the side-by-side method, leaving all notes at the bottom of the chapter or the end of the book. The HTML web reproduced the newer style. Links lead you off to a different page, not to the right side of the present page.
More exalted scribes in monasteries added plenty of drawings along with the comments, sometimes illustrative and sometimes humorous. This form of comment is preserved in print with the old Ornaments, used in advertising and posters.
And on the web, of course, with emojis.
Polistra's Mill 