In 1969 Boetti began the series of work ‘Cimento dell’armonia e dell’invenzione’. The first example of Cimento dell'armonia e dell' invenzione also known as 42 ore was supplemented by a recording of the silence and soft noises during the time it took to make. The title of this new kind of drawing refers to Vivaldi’s Opus n. 8, containing the twelve concertos which include the Four Seasons, as well as to a type of music played by Boetti himself producing compositions based on the proliferation of numbers as musical rhythms. ‘Cimento’ means contest, in this case a contest on paper on how to do musical scales.