In Paris, his musical vocabulary established, Villa-Lobos solved the problem of his works' form. It was perceived as an incongruity that his Brazilian impressionism should be expressed in the form of quartets and sonatas. He developed new forms to free his imagination from the constraints of conventional musical development such as that required in sonata form. The multi-sectional "poema" form may be seen in the "Suite for Voice and Violin", which is somewhat like a triptych, and the "Poema da criança e sua mamã" for voice, flute, clarinet, and cello (1923). The extended "Rudepoêma" for piano, written for Rubinstein, is a multi-layered work, often requiring notation on several staves, and is both experimental and demanding. Wright calls it "the most impressive result" of this formal development. The "Ciranda", or "Cirandinha" is a stylised treatment of simple Brazilian folk melodies in a wide variety of moods. A "ciranda" is a child's singing game, but Villa-Lobos's treatment in the works he gave this title are sophisticated. Another form was the "Chôros". Villa-Lobos composed more than a dozen works with this title for various instruments, mostly in the years 19241929. He described them as "a new form of musical composition", a transformation of the Brazilian music and sounds "by the personality of the composer".