The logo
is inspired by the beautiful three circles theorem:
if three congruent circles pass through a common point, then
their other three intersection points lie on a fourth circle of the same
radius.
This theorem is also known as the five-lei coin problem because
the statement was accidentally found by Gheorghe Titeica in 1908, by
drawing circles with a coin. In 1908 it was proposed as
a problem at the competition organized by Gazeta Matematica.
For an excellent survey on extensions and applications of Titeica's
theorem to
- Euclidean geometry,
- descriptive geometry,
- elementary geometry in Minkowski planes,
- Clifford configurations,
- combinatorial geometry,
see the paper The three-circles theorem, Clifford configurations, and
equilateral zonotopes by Horst Martini, in Proceedings of
the
4th International Congress of Geometry, Thessaloniki 1996,
(N.K.Arté miadis and N.K.Stephanidis, eds.), p.281-292.