“…The development of high-order DG methods for the numerical solution of Maxwell's equations in the time domain has been a particularly active area of research [13,14,15,16,17,18,19,20,21]. As the automatic generation of unstructured hexahedral meshes is still an open problem [22,23], most attention has been directed towards the use of unstructured triangular and tetrahedral meshes, in order that fully automatic mesh generators can be employed.…”