Filippo Baroni

Pictures

A butterfly in a tetrahedron

A butterfly in a tetrahedron (tap to start the animation).

It is a very strange butterfly indeed. Its body consists of four segments having a common endpoint, and it has six wings. Each wing spans two segments, and each pair of the segments is spanned by exactly one wing.

S. Matveev, Algorithmic Topology and Classification of 3-Manifolds.