This is all much clearer with examples,
and while there are some examples in the book,
they may make the whole thing seem harder than it has to be.
The book generally makes do with as few equations and variables as possible,
which has the advantage of keeping the thing short,
but at the disadvantage of making each equation hard to find.
So I've done an example where there are many equations and many variables
but each individual equation is very simple and easy to think of.
Check out the video:
Or download it: WebM format, Ogg Vorbis format, MPEG-4 format.
This web page and the files linked from it were written in 2015 and 2016 by Toby Bartels, last edited on 2016 September 2. Toby reserves no legal rights to them. The linked files were produced using GIMP, recordMyDesktop, and Libav and converted from Ogg Vorbis to other formats by online-convert.com.
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