7.13.1 Top new questions this week

7.13.1.1 How to draw a 'halftone' spiral made of circles in LaTeX?
7.13.1.2 Diagonal brace with nested parenthesis
7.13.1.3 Writing in Ancient Greek with babel
7.13.1.4 How has plain.tex been updated?
7.13.1.5 Fibonacci macro
7.13.1.6 Ackermann Function
7.13.1.7 How to adapt font size in subscript to provide a coherent look
7.13.1.1 How to draw a 'halftone' spiral made of circles in LaTeX?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584455

I would like to use LaTeX to draw a spiral like the one below, but it's way out of my league. Any help would be much appreciated. 
NEW EDIT: (now with a better 3d look!) after playing a bit with ... 
[tikz-pgf]
 
asked by JoA~\[Sterling]o LourenA~\[Section]ohttps://tex.stackexchange.com/landing/r/digest?cta=user&id=73964 29 votes
answered by Jasper Habicht https://tex.stackexchange.com/landing/r/digest?cta=user&id=47927 46 votes
7.13.1.2 Diagonal brace with nested parenthesis

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584607

I would to obtain a result similar to the image below. 
So far I only have \bigg( \Big(   \big( a^q \big)^q \Big)^{\rotatebox{25}{$\cdots$}} \bigg)^q, without the brace. 
I tried to follow this question,... 
[brackets] [underbrace]
 
asked by Watson https://tex.stackexchange.com/landing/r/digest?cta=user&id=94816 16 votes
answered by campa https://tex.stackexchange.com/landing/r/digest?cta=user&id=82917 15 votes
7.13.1.3 Writing in Ancient Greek with babel

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584397

I'm using babel to write in ancient greek. 
I'm interested in LGR Latin transliteration, which is described in the following table (taken from here): 
Everything worked fine, except for the perispomeni ... 
[babel] [babel-greek]
 
asked by rmdmc89 https://tex.stackexchange.com/landing/r/digest?cta=user&id=174335 10 votes
answered by egreg https://tex.stackexchange.com/landing/r/digest?cta=user&id=4427 13 votes
7.13.1.4 How has plain.tex been updated?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584572

I've noticed that on CTAN there is a new version of the file plain.tex, dating 2021-01-17.  But nowehere I see what the changes are.  What has changed? 
[plain-tex]
 
asked by User https://tex.stackexchange.com/landing/r/digest?cta=user&id=43121 9 votes
answered by David Carlisle https://tex.stackexchange.com/landing/r/digest?cta=user&id=1090 6 votes
7.13.1.5 Fibonacci macro

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584474

I am trying to make a Fibonacci macro, that works as follows. 
I was able to do so, and I tried to make everything private by using @ (i know it isn't necessary here, but I am trying to practice...). ... 
[macros] [errors] [loops] [recursion] [robust-commands]
 
asked by needle https://tex.stackexchange.com/landing/r/digest?cta=user&id=235026 8 votes
answered by David Carlisle https://tex.stackexchange.com/landing/r/digest?cta=user&id=1090 9 votes
7.13.1.6 Ackermann Function

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584112

I am trying to write a macro to evaluate the result of the Ackermann function. 
If anyone doesn't know it, is defined as follows: 
So I am trying to write a code that is able to compute it but I can't ... 
[macros] [errors] [recursion] [robust-commands]
                                                                                  

                                                                                  
 
asked by needle https://tex.stackexchange.com/landing/r/digest?cta=user&id=235026 6 votes
answered by Ulrich Diez https://tex.stackexchange.com/landing/r/digest?cta=user&id=118714 12 votes
7.13.1.7 How to adapt font size in subscript to provide a coherent look

https://tex.stackexchange.com/landing/r/digest?cta=question&id=584524

I'm trying to define a nice arrow with a dollar above (not too small to make sure it's easy to read, not too big to make sure it does not change the line height too much). 
I came up with the below ... 
[math-mode] [spacing]
 
asked by tobiasBora https://tex.stackexchange.com/landing/r/digest?cta=user&id=116348 6 votes
answered by egreg https://tex.stackexchange.com/landing/r/digest?cta=user&id=4427 5 votes