Wiki Information – https://en.wikipedia.org/wiki/Carnaval_%28Schumann%29 –
Carnaval, Op. 9, is a work by Robert Schumann for piano solo, written in 1834–1835, and subtitled Scènes mignonnes sur quatre notes (Little Scenes on Four Notes). It consists of 21 short pieces representing masked revelers at Carnival, a festival before Lent. Schumann gives musical expression to himself, his friends and colleagues, and characters from improvised Italian comedy (commedia dell’arte).
The four notes are encoded puzzles, and Schumann predicted that “deciphering my masked ball will be a real game for you.” The 21 pieces are connected by a recurring motif. In each section of Carnaval there appears one or both of two series of musical notes.