 Apart from these, various ensembles have commissioned compositions, such as a string quartet for Walpurgis and the tone poem 's Nachts brede opklaringen for the Spiegel Strijkkwartet.Major compositions include the oratoria or mini-operas "Music Hall" on poems by Paul van Ostaijen for Prima la Musica, "The Soluble Fish" and "Charms" on poems by Daniil Kharms, both for Walpurgis.The grand big-band opera "Heliogabal" was written for the Ruhr Triennale and performed by the Flat Earth Society.