Carbon nanotubes are very promising new materials that tit perfectly well into the miniaturisation of technology, but at the same time show a fascinating quantum structure. When the tube is closed to form a torus the structure acquires discrete molecular characteristics. In the present paper the electronic levels of tori are obtained by a double folding of the Brillouin zone of graphitic carbon. An illustrative example of an hypothetical giant torus with molecular symmetry is fully analysed, with special emphasis on its pictorial representation.