[userbinator]

The "square root by subtraction" seems like the same algorithm that can be "implemented" by hand relatively easily on early mechanical calculators:

https://www.youtube.com/watch?v=K_c9-Y1ouww

[dahart]

What is this thing?? I totally have no use for it, and still I want one.

I'm very not sure what it's doing, but it looks like a different algorithm to me; there are a surprising number of square root techniques. https://en.m.wikipedia.org/wiki/Methods_of_computing_square_...

[j_s]

ReCurta: Our goal is to build the first Curta calculator since 1972 | https://news.ycombinator.com/item?id=16035091

[userbinator]

It's a Curta: https://en.wikipedia.org/wiki/Curta