6.66.3 Can you answer these questions?

6.66.3.1 Drawing the Bernoulli lemniscate with level curves

https://tex.stackexchange.com/landing/r/digest?cta=question&id=571382

I would like to draw the Bernoulli lemniscate (see below): 
However, I would like to draw it in a similar way as the picture in the following question, which has already been answered: Relation ... 
[tikz-pgf]
 

asked by rkrapf https://tex.stackexchange.com/landing/r/digest?cta=user&id=187521 1 vote

6.66.3.2 Weird index sorting display using tufte-book

https://tex.stackexchange.com/landing/r/digest?cta=question&id=571096

I am using tufte-book for creating the document and makeidx for creating the index. The three column index generates correctly, but it displays it in a weird manner. Instead of alphabetical entries ... 
[indexing] [tufte]
 

asked by Damitr https://tex.stackexchange.com/landing/r/digest?cta=user&id=43555 1 vote

6.66.3.3 Is JASA documentclass not working?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=571200

I have the following "minimal example" which is not working: 
%%%%%%%%%%%%%%%% 
\documentclass[preprint]{JASA} 
\begin{document} 
\title{My Title} 
\author{My Name} 
\begin{abstract} 
... 
[document-classes]
 

asked by mvs https://tex.stackexchange.com/landing/r/digest?cta=user&id=136810 1 vote