Invented on May 18th, 2007 (by Oleg Ivrii and Zavosh Amir-
Khosravi) a "rigorous" defintion of CoolStuff is against our
philosophy, so I will only give some guidelines what qualifies
stuff to be cool: - The process of CoolStuff is to learn
mathematics by application. Here at CoolStuff, we believe that
to understand a subject is to see it used in action. - By its
nature, it is elementary, simple, elegant and intuitive.
Sometimes, it could even be accessible to highschool students if
it did not use a simple fact from topology or abstract algebra.
Nevertheless, CoolStuff benefits from its highly intelligent
audience. - CoolStuff does not belong to a single subject, it
draws from all of mathematics. By its nature, it cannot be found
in a university classroom, which tries to partition all of
mathematics into "subjects". - CoolStuff should be able to stand
by itself as a final result, with no applications in mind (even
though, applications make it even more cool). - When it is a
well-known theory, the focus is on sh