This chapter consists of a very intuitive, but rather comprehensive at the
same time, introduction to border patterns. The presentation is wholly
geometrical and almost entirely self-contained: the material is presented
in such a way that it may in fact be used to introduce planar isometries
(with the exception of rotations other than the half turn). Emphasis is
placed on the relations among the seven different types of border patterns
and on how one could 'pass' from one type to another. Just like in the
rest of the book, no Group Theory is involved; still, a 'rough
classification' of border patterns is presented.