The French designer Mathieu Lehanneur is known for creating both artful furniture and lighting as well as electronics, with a rare technical craftsmanship that combines art and design with science and technology. For his latest presentation, at New York’s Salon Art + Design fair, on view through Nov. 18 at the Park Avenue Armory, Lehanneur responded to the history of the building itself—a late 19th-century brick Gothic Revival structure, formerly the headquarters for the 7th regiment of the New York Militia—with “Soldier’s Retreat,” a collection of objects that embody the natural elements, seemingly frozen in time.