Architect Daniel Libeskind is suing the developer of the World Trade Center site. “In court papers filed July 13, Mr. Libeskind claimed that Mr. Silverstein owes his firm $843,750 for the architectural work it performed on the Freedom Tower between July and December of 2003. Mr. Silverstein allegedly last offered around $225,000 for the work, a figure that Mr. Libeskind has called “insulting,” and which he has said is in retaliation for the way his vision for the skyscraper clashed with that of Mr. Silverstein’s architect on the project, David Childs, of Skidmore, Owings and Merrill.”