This paper is written for those Gymnasium students with an
intensive interest in mathematics who are often in search for some
extra reading matters not being on school curriculum. We have
chosen to elaborate here a number of interesting and beautiful
geometric topics: the diagonals of polygons and the
triangulations, the art gallery theorems, the Euler formula,
regular polyhedra, that could satisfy their curiosity and
instigate their further reading.
Keywords: Diagonals of polygons,
triangulations, art gallery theorems, Euler formula,
regular polyhedra.