Formulae E-volver (2015) is a software that allows visitors to influence the growth of visuals via a touch screen. The software composes mathematical formulae from elementary building blocks and visualizes them in the form of animated black & white images. The least interesting animation will be deleted by the viewer. Formulae that were displayed for a long time have more chance to crossbreed, whereby visual properties are mixed and passed on to future generations. On the basis of personal preferences of the user, the system will gradually evolve formulae that generate complex intriguing visuals.