qnli question: What two activities did Frédéric do while visiting for a day in Düsseldorf with Mendelssohn and Hiller? sentence: They spent what Mendelssohn described as "a very agreeable day", playing and discussing music at his piano, and met Friedrich Wilhelm Schadow, director of the Academy of Art, and some of his eminent pupils such as Lessing, Bendemann, Hildebrandt and Sohn.