Hi Yagiz
> Is it related to the Scala Puzzlers that are online?
Just on this part of your question: the puzzlers covered in the book are a subset of those listed on the site. In the book, we explain the reasons behind each puzzler in much more detail, talk about alternative approaches you can use, and suggest best practices for avoiding puzzling code. See
Nermin's comment in a different thread for some links that will help you compare the two.
Regards
ap