 Perhaps the most controversial aspect of the concertos is the extent to which Mozart (or other contemporary performers) would have embellished the piano part as written in the score.Mozart's own ability to improvise was famous, and he often played from very sketchy piano parts.Furthermore, there are several very "bare" parts in the concerto scores that have led some to deduce that the performer is meant to improvise embellishments at these points, the most notorious being towards the end of the F-minor second movement of No.