The real world was far too real to leave neat little hints. It was full of too many things. It wasn't by eliminating the impossible that you got to the truth, however improbable; it was by the much harder process of eliminating the possibilities.
Terry PratchettRacism was not a problem on the Discworld, because - what with trolls and dwarfs and so on - speciesism was more interesting. Black and white lived in perfect harmony and ganged up on green.
Terry Pratchett