GUBI Demon Shelf - 1 Shelf - The Demon Shelf, or the Biblio-Demon as it is listed in Mategot’s old sketches, was part of a “plan d’execution de la bibliothèque” - the model of an interior home library and study. The modular shelving system, designed in 1954 by Mathieu Matégot, can be applied in multiple ways suited for all homes and spaces where that extra dimension of aesthetics for wall storage is sought for.