^^Ins consigli.

I believe in the maxim that

• it is more instructive to give different proofs to the same result
  than the same proof to get different results.

Much attention is paid to examples:

• the best way to understand a general concept is
  to study in detail the first non-trivial example.

ref: Geometry and billiards.pdf by Tabachnikov, e' solo la prefazione.

ref: stml-30-prev.pdf  i primi 4 capitoli