Once per year, l'École des Arts Décoratifs de Strasbourg opens its doors to the public. On this occasion the school grounds, the classrooms, its walls and the streets around are transformed by the students into a huge exhibition space. I led here the Roulez Gazon project : in two days, we filled a forty square-meter room with real grass hills, planted flowers and have been watering it until the visitors came. There, lying in the grass, one could enjoy the invited jazzband improvisations, taste herbs, or hunt for the couple of hidden Easter Eggs.