This book project extends the one made in 2012, La courbe de la ritournelle, published by Filigranes, which documents four large installations exhibited at the Frac Alsace, at the Kunstraum in Dornbirn, Austria, and at the Abbaye de Maubuisson, in 2008, 2010 and 2011 respectively. It also aims at a transversal approach to Jan Kopp's work, developed here over the last three years, and focuses on three large-scale constructions: those at the La Criée art centre in 2013 (Grand Ensemble), at the Centre Pompidou in September 2014 (A 2000 mètres d'ici) and in 2015 (Soulever le Monde). Each time they are precarious, free architectures, built with borrowed or salvaged materials, put together by several people and destined to disappear. Grand Ensemble thus gathered several hundred rod- or wand-shaped objects of metal, wood, plastic and so on, collected from the inhabitants of the city of Rennes and assembled in the art centre to form a sort of forest perched on long crutches.