At first he was made as a palette swap of Mario with a green color instead of red. Later in the series, he became his own character with his own personality and abilities. As his part in the "Mario" series progressed, Luigi became taller and thinner than his brother. Nintendo called 2013 "The Year of Luigi" to mark the thirty years of the existence of the character. Similarly, games being released in 2013 bring attention to Luigi, such as , "", "Dr. Luigi", and the level pack "New Super Luigi U" for "New Super Mario Bros. U". In "Super Mario 3D World" a Luigi version of "Mario Bros." called "Luigi Bros." can be unlocked.