Here are two demos. Both have been created using compo with Open Music. Though they are presented here using the Open Music version, for clearness reasons, all the proposed concepts belong to compo and are actually accessible, though in a different way, in the compo language. For lisibility reasons, these demos have been optimized for a display in high resolution (1024x780), required by the density of the graphisms presented. We apologize to persons using a computer not able to display in such a resolution. compo - basis present the basis of compo through a little lego game, more pedagogical than really practical. compo - 4 voice canon really enter into the subject by describing the construction of an already complex musical structure, from a rather academic, but nevertheless significant example, borrowed from a classical counterpoint treatise (Théodore DUBOIS for who is interested in).