In 1999, a group of respected scientists, along with the American Chemical Society, launched a journal called Organic Letters, designed to rival Tetrahedron Letters, a chemistry title owned by Reed Elsevier.

ECONOMIST: Publishing

When Cluster II passes through these so-called polar cusps, instruments on board each of its satellites will measure the magnetic field, electrical current and number of charged particles within the tetrahedron.

ECONOMIST: Birds of a feather

Three, the tetrahedron, octahedron and icosahedron, have triangular faces.

ECONOMIST: The shape of the universe