The figures
are not included as window dressing, in fact they play an
important role in bringing the reader to a robust understanding
of the mathematics. However they are not only instructional, they
are also fun!
For example,
on the right is a crazy Pacman path  created with linear transformations
and a bit of coloration thanks to Postscript
Below, left
is an instructional tool used to demonstrate a rotation by 45 degree,
and below right is simply a fun example of what we can do with 3D
transformations.
