I do have a multi-chapter series on constant-time integer arithmetic -- indeed tagged incl. "bitcoin", as it is meant to be used in (among other places) a rework of the client.
You evidently spent at most 3 seconds reading the link; wouldn't kill you to spend 5 seconds and see what is behind the tag.
One of the attractions of Hypercard was that a "stack" (document) was entirely self-contained; and would always behave exactly the same on any machine where HC could run.
Notably, would run without any need for servers (or, worse, the subscription-and-lock-in "services" ubiquitous today -- arguably the 1980s "computer revolution" was strangled in the cradle, and we've gone most of the way back to 1970s-style time-sharing now: how many phone apps etc. will run usefully without a net connection? The "smartphone" is essentially a small "glass TTY", rather than personal computer in the '80s sense.)
I've run HC stacks written 30+ years ago. How many current-day "web app" documents will be readable as-found 30 years from now? For that matter, I've paid for iOS apps that would no longer execute after half a year (on account of Apple's "API changes", or in some cases -- author's "call home" server fell down and did not get up, etc.) Permanence (in the most basic "I paid for this and it ought to be usable for so long as any compatible iron remains functional" sense) is no longer part of the software commercial culture, and one is likely to be laughed at for merely raising the question.
Author of linked piece speaking. Seems like many readers continue to miss the essential point, just as they did in 2011:
Hypercard wasn't a gem of graphic design (1-bit colour, plain line graphics) or of programming language design (one of the many laughable attempts at "natural language programming") or of high-performance number crunching... but it was simple. I.e., the entire system was fully covered by ~100 pages of printed manual. It fit in one's head. (And did not take 20 years to fit-in-head, either, an intelligent child could become "master of all he surveys" in a week or two.)
Where is the printed manual for the current MS VB, or the WWW's HTML/JS/CSS/etc stack (yes including all browser warts), or for any of the other proposed "replacements" ? How many trees would have to be killed to print such a manual, and would it fit in your house? Could you read it cover to cover, or would die of old age first?
You evidently spent at most 3 seconds reading the link; wouldn't kill you to spend 5 seconds and see what is behind the tag.