> For the complete documentation index, see [llms.txt](https://erroldrummond.gitbook.io/snark-fundamentals/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://erroldrummond.gitbook.io/snark-fundamentals/part-3.md).

# Part 3. Proof systems in the wild

Now that you have an idea about all the most basic building blocks used to create a SNARK, let’s explore some popular proof systems. A proof system is how a proof becomes real. Each system uses different methods for creating circuits and comes with different advantages and trade-offs. As an analogy, if a proof is a car, then the proof system is the design of the car factory.