1. Madonna with Child and Saint Anne, by Leonardo da Vinci (1501-1510)

2. Portrait of Pope Leo X with two Cardinals, by Raphael Sanzio (1517-1518)

3. Concert, by Michelangelo Merisi da Caravaggio (1595)

4. The Dukes of Osuna with their Children, by Franciscus Goya (1788)

5. Three Worlds, by Maurits C. Escher (1955)

6. Pottery, by Patrick Caufield (1965)