2.24.3 Can you answer these questions?

2.24.3.1 Need help in understanding answer to "how-to-make-beamer-overlays-with-tikz-node"?
2.24.3.2 How often refer a list of symbols
2.24.3.3 No vertical spacing between TikZ Pictures

Can you answer these?

2.24.3.1 Need help in understanding answer to "how-to-make-beamer-overlays-with-tikz-node"?

http://tex.stackexchange.com/questions/317244/need-help-in-understanding-answer-to-how-to-make-beamer-overlays-with-tikz-node

Can someone explain this code. 
How to make beamer overlays with Tikz node. 
In particular I need to know 
Why do we get three copies of a given slide. If I need to make more than two copies, what  ...
 
- asked by NAASI 3votes
2.24.3.2 How often refer a list of symbols

http://tex.stackexchange.com/questions/316546/how-often-refer-a-list-of-symbols

I know how to make a list of symbols with the help of glossaries, but I am facing a style problem that I'd like the community help me solve. 
I writing my thesis in mathematics, so I have many  ...
 
- asked by dadexix86 3votes
2.24.3.3 No vertical spacing between TikZ Pictures

http://tex.stackexchange.com/questions/317026/no-vertical-spacing-between-tikz-pictures

I would like to have absolutely no vertical space between the two TikZ Pictures. 
I could use for example \\[-1pt] but I don't know if 1pt is really the exact value... (so I removed it from the code)! 
...
 
- asked by micmic 7votes