With regard to copyright, it's usually a question of quantity. Up to 10 lines of code is often regarded irrelevant for copyright purposes. Of course, it's not a

With regard to copyright, it's usually a question of quantity. Up to 10 lines of code is often regarded irrelevant for copyright purposes. Of course, it's not as simple as that: 10 lines in how concise a language, etc. But it's not a big problem most of the time, in the same way literary or other human-language text is copyrighted but it's still acceptable to quote and cite. But ideas themselves don't fall under copyright; unfortunately, some countries allow the patenting of software algorithms, which do cover the idea to some extent.