La Bissectrice du cône is a mixed piece written for the Bol. Created with a simple instrument consisting of a membrane and a stainless steel bowl. The contact between the compressed air and the membrane gives a spectral richness that I had to put forward. The sounds from the materials of which the Bol is made are therefore the premise of the project. The composition allows the project to evolve with the algorithmic permutations that the sound underwent. It is a ray protruding from the top of the angular sector. The line is drawn following the rules that seems to be imposed by these circles of colours. A system erects itself so that the geometry of its shapes may shine its rays anew.