INVISIBLE CITIES [30] -- Trading Cities: EUTROPIA

1. So, chapter 4 motif?
2. Back to Calvino's imagination: hasn't he proved himself?  Isn't it good enough?  Is it overkill to keep going with more and more "invisible" cities?  Can you identify--or at least feel--a progression?
3. What of the absurd impracticalities (and thus indulging the impossibilities) of such a place?  Maybe the fact that no one spends more than a year or two at any one job has something to do with the overall level financial playing field.  Of course, that begs the question: if they're happy anyway, do they need the money or influence or power that comes by and/or causes class stratification?
4. Define the irony of the last two sentences: "Alone, among all the cities of the empire, Eutropia, remains always the same.  Mercury, god of the fickle, to whom the city is sacred, worked this ambiguous miracle."