La Joconde aux clés Cubist Fernand Léger (1881–1955) was influenced by industrialism. His “La Joconde aux clés” from 1930 (58 x 76 cm) features “La Gioconda,” the wife of Francesco del Giocondo, painted in 1503–06 by Leonardo da Vinci – better known as Mona Lisa – with a set of modern keys. Léger was a soldier in the First World War. He stayed in the United States during the second and returned to France in 1945. Soft pop-art key Pop-art sculptor Claes Thure Oldenburg invented his vinyl Soft Key in 1965. It was a standard cylinder-lock key, beige, measuring 92.5 x 44.4 x 2.5 cm. Oldenburg was born in Stockholm in 1929 and studied English literature and art at Yale University in New Haven, Connecticut, in 1946–1950. In 1956 he moved to New York. The author’s keys Like Léger, German author Günther Grass has been inspired by a set of keys. The picture shows three keys, a glass goblet, two mushrooms and a fish. Keys in circulation Depictions of keys are even found on coins, stamps and matchboxes. Swedish and Czech matchbox labels from the early 20th century. Photo by the author.