You might not have heard of the design firm Pentagram, but more than likely you’ve seen its work. Pentagram designed the shopping bags for Saks Fifth Avenue, the logo for Citibank, the layout of the New York Times Magazine. In short, its designers make things look pretty. Recently, Pentagram got a call from the nonprofit Nature Conservancy. As Hammad Ahmed reports for The Environment Report the week of July 6, 2009  , it wasn’t the usual request for a nice new logo or packaging.