The golden rule is silence. Before a strong work — a Soulages, a Fontana, a Polke — furniture must efface itself without disappearing. In scenography this is called the seat function: a chair, a table, a bench must sustain the gaze without diverting it. Paradoxically, it is often the most designed pieces — those of the great twentieth-century Scandinavian or Italian masters — that best achieve this purity, because their line is so exact that one ceases to notice it.