As towns continue to grow, replanting vegetation has become a form of urban utopia and green roofs are spreading fast. Last year 1m square metres of plant-covered roofing was built in France, as much as in the US, and 10 times more than in Germany, the pioneer in this field.

Usually there was a jug of one or other decoction standing on the hob, from which he drank largely. Grand! he said, smacking his lips after wormwood. Grand! And he exhorted the children to try.

Eventually, a renewed edifice may grow large enough even to bury its somma, or sommas, completely, leaving no clue in its shape to a history of former catastrophe(s).

However, you have to realize that you should measure the costs and payoffs in utilons, not in dollars. $1 is almost infinitesimally small (in utilons), while $1M payoff is huge - it is perfectly rational to buy the ticket.