“This study symbolizes an attempt to insert oblique architecture into reality […] the oblique leaves its splendid theoretical isolation behind, and steps into the century.” This is how Claude Parent tells the story in 1981 in his book entitled Entrelacs de l'oblique (the comment by Bruno Zevi.) This manifesto-building was a project for a competition, which he lost, for the French oil-drilling company Elf-Erap in Libreville. The architect proposed a simple plan aligned on an axis where two square buildings of varying size are placed face to face. Communication with the street is achieved by means of a long inclined plane that doubles as a public garden and space for circulation for the agents of ELF and the population of Libreville. Although the building appears open to the city, it in fact presents an entire, more discreet, secondary network of circulation and spaces. The seven floor building was to bring together one roof the offices of the oil company and the galleries of the National Museum of the Arts and Traditions of Gabon. Here, public and private effortlessly blend in this tall (a panoramic view of the city and the ocean for the museum on the top floor) and enveloping (public garden) structure. The three oblique circulation approaches, far from obscuring the façades, allow one to perceive the entire glass elevations over almost four levels, broken vertically only by thin ribbons of concrete. Here, the architectural and urban theory of the Oblique Function took the architect along a path of research into innovative forms in which he grouped habitat and circulation in a coherent composition open to the exterior. Projects have enabled Claude Parent to express himself but drawing has led him to an in-depth investigation of the question of the right form, as demonstrated by the series of Les Assauts (1973), in which an emerging monolithic form is encircled and extended by three inclined planes. Ultimately, the winning project for ELF was the one designed by Lesne, Bernadac and Eliescou. Their building, echoing the nearby ocean, takes the form of a wave with a façade inclined at approximately 12%.