“Lighting is technical but at the same time, it’s emotional.”

As Salone del Mobile turned Milan into a madhouse of design, there was one quietly eloquent exhibit that seemed to speak a different language. In a solemn space as pristine white as a laboratory, lights traced circular orbs on the floor and scored walls with glowing colors. While others vied to define the latest shapes, shades and materials of design, the Italian duo of Formafantasma took a more disquisitive tack, showing 16 lamps where the principal material was light itself. Each was spare in form with magical results, with the light sharpened through a magnifying lens, striated through colored glass or bounced off of polished brass. Weary explorers of Milan’s overwhelming design week stood suddenly wide-eyed in the room, trying to capture images of the enchanting effects.

“Lighti...