The 1930s was even more fruitful , with the Concerto for Two Pianos , Choeurs , Saxophones and Orchestra , the Violin Concerto , the operas Zoulaïna and Le marin de Bolivar , and her masterwork , La cantate de Narcisse in collaboration with Paul Valéry .
In the 1930s she composed the Concerto for Two Pianos , Choeurs , Saxophones and Orchestra , the Violin Concerto , the Operas `` Zoulaïna '' and `` Le Marin de Bolivar '' , and her masterwork , `` La Cantate de Narcisse '' , which she wrote with Paul Valéry .