Projects for beginners

[Richard Kenner]

    NO!!!  I remember well the days of unguarded headers.  They are not
    completely dead yet, but I still hope for their final demise.  I do
    not ever want to _have_ to know that header a can be included only
    after header b.  Programming is complicated enough without just that
    much more clutter.  NO, NO and NO AGAIN!

If the structure of the headers is so complicated, it needs to be
simplified. The perceived need to put in "guards" is merely a symptom
that things have gotten too complicated.  They should be made simpler,
not patched over by adding the clutter of guards.