Of Le Corbusier's architecture-metaphors, the best known is surely that which likened a house to a machine, but he made many others. His early houses at La Chaux-de-Fonds alluded directly to the fir trees that grew beside them. His Armee du Salut building, particularly its upper storey as it meets the sky, assumes the profile of an ocean liner. In studies for Rio, Monte Video, Sao Paulo, and Algiers, his buildings are like bridges to be driven over; and in both visual and verbal writings, Le Corbusier variously likened his elephantine Unite d'Habitation at Marseilles to an ocean liner, a filing cabinet and a wine rack.