Works are thought through to the end, but sometimes not by those who have started. Mozart’s student Franz Xaver Süßmayr completed his requiem. Franco Alfano left a final for Giacomo Puccini’s last opera Turandotwhich later also avant -gardist Luciano Berio did for the Salzburg Festival. There are also attempts to think of Mahler’s tenth symphony. And the tenth of Beethoven even came in the rather cramped enjoyment of a AI reconstruction.