BOSTON, MA .- AD 20/21: Art & Design of the 20th & 21st Centuries, the only annual art and design show of its kind, will honor design visionaries Massimo and Lella Vignelli with a Lifetime Achievement Award at its fourth annual show April 7-10, 2011 in Boston. For over 50 years, Massimo and Lella Vignelli have achieved renown as two of the most innovative minds in the design community. Their work includes countless graphic and corporate identity programs and exhibition, interior, furniture, and consumer product designs for many leading American and European companies and institutions. Massimo Vignelli is also widely known for his design of the iconic 1966 New York City subway map. The award will be presented at the Gala Preview on Thursday, April 7, which benefits Boston Architectural College. On Friday evening, Apri