I was fiddling around with LaTeX and wrote a short introduction. Anyway, here it is, complete with all spelling and punctuation mistakes.
Meanwhile, I noticed two things. One, a mistake in how I handle some comparisons. And two, how convenient it would be to be able to build lists which holds values of different types but which are constrained to the same interfaces.
021910: New link with some small changes after some hints on LtU.