The American artist Joseph Kosuth’s neon lights illuminate the palace façade. An exponent of conceptual art, he has shaped the neon tubes to trace primordial words: Abstract lines, Forms of earth (crystals), Forms of water (waves), Forms of air (clouds), Organic forms (shells). The installation totals twelve illuminated signs placed at different heights: this is The Material of the Ornament, 1997. Kosuth was inspired by John Ruskin’s The Stones of Venice (1851 – 1853). The classification of decorative architectural elements into categories devised by the English art critic thus becomes an ornament itself, activating unexpected relationships.