It is so large that when they have finished painting it, it is time to start over again. In reality, I'm told, they look for bits of the bridge that need painting and paint them. So it is true that they keep on painting, but they do it discretely, not continuously. For some reason, Rincewind has problems with the word 'aeons'. Before me things create were none, save things Eternal, and eternal I endure.
All hope abandon, ye who enter here.
At the centre, in the 9th circle, Lucifer sits chewing away on Brutus, Crassus and Judas. The chap who had to go through to the same thing in the Underworld was the giant Tityus, who had tried to rape Leto, the mother of Artemis and Apollo. Man who went and defied the gods or something. In Greece she was called Persephone, daughter of Ceres, the goddess of agriculture. Hades abducted Persephone, imprisoned her in the underworld, and took her for his wife.