Obviousness - Prior Art

This Youtube clip that our Professor sent us was very helpful in determining what exactly is prior art and how it is so useful in determining if something in non-obvious. Non obvious, according to the video, is something that cannot be assembled by using prior art. The clip then delved into how to find prior art. The main way to do so is to search for published articles on the subject matter and then go from there. Also, existing products can be used as prior art since they have too been "published" and are likely patented. What I found interesting was that the narrator used code as an example of prior art as well though I am not sure how you would find such large published code structures besides stack overflow and github. Also, I thought one could not patent code which was also something I had a question about because of algorithms which are like mathematical theories couldn't be patented but a machine that runs them could be. Finally, a fun fact from the video was the Thomas Jefferson was the first patent examiner though now there are so many because of how many directions our world is growing.