sentences:  At the opening of his Berlin exhibition in 2004, he presented another action, this time aimed at the art world.He arranged for six security guards to prevent the public from any contact with the art, the objects, and other people, all under a prohibition sign that said "Do it right".For "One Ton Of Books Dumped On Reform Avenue," a dump truck stopped in the middle of Guatemala City's Avenida La Reforma, a major artery, dumped its load of used books, and drove away.