- Regular tetrahedron (Wikipedia)
A regular tetrahedron is a tetrahedron in which all four faces are equilateral triangles. In other words, all of its faces are the same size and shape (congruent) and all edges are the same length. A convex polyhedron in which all of its faces are equilateral triangles is the deltahedron. There are eight convex deltahedra, one of which is the regular tetrahedron.
- Alexander Lebedev (Wikipedia)
Alexander Yevgenievich Lebedev (Russian: Александр Евгеньевич Лебедев, IPA: [ɐlʲɪˈksandr jɪvˈɡʲenʲjɪvʲɪtɕ ˈlʲebʲɪdʲɪf]; born 16 December 1959) is a Russian businessman, and has been referred to as one of the Russian oligarchs. Until 1992, he was an officer in the First Chief Directorate (Foreign Intelligence) of the Soviet Union′s KGB and later one of the KGB’s successor-agencies, Russia’s Foreign Intelligence Service (SVR).