sentences:  This explanation of the origin of the keyboard is in conflict with the Western consensus story that the pattern on the keyboard evolved culturally from originally seven white keys, adding one black key, followed by more into the twelve-tone Halberstadt Keyboard from 1361.In December that same year Musical Instrument Museum put on a large overview exhibition of his invented instruments.In 2019 he build a follow up series of rhythmic helicopters as a part of 's '7090 Abstraction Parc' that was exhibited at Gaudeamus Music Week, Open NDSM and several other Dutch festivals.