Well done for actually trying and failing to reproduce their results.

But the point from the original comic version kind of makes it seem like specs are useless, which I don't believe is true. Just like reimplementations can be useful (directly so for property testing or golden testing, but also for learning what things worked and what didn't), a specification can be useful even though it is informal or incomplete in that it guides the real implementation. (Like "plan mode", for you vibers.)

It's so easy to make a specification which can't be implemented (or shouldn't be). Very often, I go back and tweak the specification, after I start the implementation and figure out which assumptions are wrong ...