I'm as confident that there isn't an invisible, indetectable pink unicorn standing behind me as I am that someone has written multiple complex and bug-free applications working only from their memory of a language and codebase. Not even Don Knuth is that much of a savant.
At the very least, the quality of such code should be self-evident and instructive.
At the very least, the quality of such code should be self-evident and instructive.