each three meters high, representing Mars, Apollo, and allegorical figures of Prudence and Liberality by the sculptor Augustin Pajou, which had been featured at the Paris Salon of 1769. On the other side of the balustrade are later statues of Commerce and Navigation and figures of Science, Agriculture, by Antoine Gerard, made in about 1830. In 1985-86 the Ministry of Culture sponsored two sculptural works in the courtyard; the first, called "Photo-Souvenir - Les Deux Plateaux", by Daniel Buren, consists of short columns of various sizes arranged across the courtyard. The idea is to create two virtual platforms, without floors; the columns vary in height because of differences in height of the illusionary platforms; some of the column rows are purely horizontal, aligned to the height of the column bases of the gallery of Orleans, while the smaller columns all rise to the elevation of a lower non-existent platform; their variation in height is caused by the difference of elevation in parts of the courtyard. Each column has vertical bands of black and white. The second work is composed of two fountains by sculptor Pol Bury, located within the roofless Gallery of Orleans, which separates the Courtyard from the gardens. It consists of two square basins each containing seventeen polished metal spheres of different sizes, with water flowing around them. The polished spheres reflect the architecture of the arcades around them. A third work, commissioned in 1994 is by the Dutch artist Jan Dibbets, passes through the courtyard of the Palais Royale. It is called "Homage to Arago", and is a tribute to the French mathematician François Arago, who first conceived the prime meridian of Paris. the north–south line passing through the center of Paris which marked the prime meridian (rather than Greenwich) on French Maps. The work consists of one hundred thirty-five brass small brass plaques with the name "Arago" fixed on the pavement on a line which passes through the Palais Royal, and extends on the same axis to the north and south across Paris. Gardens The first garden of the Palais was planted by Cardinal Richelieu in 1629, where the Court of Honor is today. In 1633, Richelieu obtained authorisation to extend the garden northeast into the land occupied by the obsolete medieval city walls of Paris. He also received permission to sell forty-five building sites around the garden. The new garden site was 170 meters by