Lluís Clotet and Oscar Tusquets designed their famous A Sardinel mailboxes in 1975, when they still worked together as Studi Per. That mailbox design was tall, narrow and deep. It was to be fitted a sardinel, that is to say, edgewise like bricks in a building or like an encyclopedia on a shelf, forming an orderly block. In this way it offered a larger capacity than traditional mailboxes, while visually occupying much less space. Its chief novelty lay in the fact that it was filled from the top, something that became important when people began to receive the first subscriptions to newspapers and magazines at home. Over the years the design evolved and was improved until the current Tres Cuatro Cinco was reached