For example, UML or something else ... Sometimes the program is already too long to scroll through it in mind, although it all started with a more or less clear plan, again in mind.
Then in some places crutches went, or the gap of several days between writing and the chain of understanding disappeared.
There are sensations that need to be optimized, but again it is difficult to restore the chain, and inspecting individual sections is not enough, since there are many interconnections.
UML Diagrams I tried earlier on primitive examples, so I don’t know how much they help. I also did not read books on optimization or refactoring, which is probably the problem.
How can we achieve an understanding of the work of the entire program in a visual form?