LONDON (AP).- A giant blue rooster and a boy on a rocking horse will stand alongside a statue of military hero Adm. Horatio Nelson in London’s Trafalgar Square. Officials on Friday announced the next two artworks to fill the square’s empty “fourth plinth,” one of the city’s major showcases for public art. Next year the platform will hold a bronze sculpture of a boy astride a rocking horse by Michael Elmgreen and Ingar Dragset. The piece is intended as a thoughtful riposte to the square’s military monuments. It will be followed in 2013 by German artist Katharina Fritsch’s ultramarine cockerel, designed to symbolize “regeneration, awakening and strength.” Mayor Boris Johnson said the “witty and enigmatic creations underline London’s position as one of the most exciting cities for art and are sure to keep people talking.” One of London’s main tourist attractions, the square was named for Nelson’s 1805 victory over