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
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.