The one contains what is accepted as necessary when it is not yet so; the others, what is imagined as possible,
and, a moment later, is possible no longer.
(Fedra: the Invisible Cities, Itaro Calvino)
Fedora is the city where anything is possible.
But a moment later ppl think about the possibilities, the possibilities become just dreams and are possible no longer.
The possible future have become impossible dreams becasue they wished them as dreams.