The complexity of wrong things far exceeds that of things intended.
References for some of the subsequent points:
The book, chapter 5, `Running ', contains
instructive examples, and supposedly `dangerous', but actually basic
and useful, notes.
In that chapter, and in chapter 27, `Recovery from Errors', KNUTH discusses the diagnosis of 's error messages. I find this perhaps the hardest part of the book — if not of using .
Incidentally, 's error messages are contained in an ASCII file called `mf.pool'. Reading the pool file can be entertaining.