After reading some projects, I find that it is not the architecture of the software that is really hard to know. It is not hard to figure out the architecture immediately if the project is clearly designed and implemented, if it's hard and never seen before, some day later I can find out some pattern similar to the one I read in the same domain.

The difficulty is that the concepts and mechanism defined by the author are really hard to guess, and these concepts may spread in the whole project which makes it hard to grasp. The situation is normal and universal and you can ask questions to your colleague when in a company. However, it gets worse if nobody around you knows these details. How do you handle these details which block your reading?