“Les Concerts du mercredi” organization offers classical music concerts to an eclectic audience. Unlike a musical recording, the conditions of space and time (condition of space-time ) make each performance unique. This observation is the starting point of our approach, which led us to develop a generative design to produce 750 different unique posters. The music and its variations are illustrated by a series of forms representing the idea of movement and gesture. For this project, a custom typeface named «Bourdonnette» was designed in two weights, sans and mono.