Hints about the Obama library? New York architects Tod Williams and Billie Tsien, co-designers of the Obama library and museum, will lecture at the Illinois Institute of Technology's Crown Hall at 6 p.m. March 29 — their first public appearance in Chicago since being selected for the project last June. It will be fascinating to see what they reveal (or don't) about the design for the project, which will be built in Chicago's Jackson Park.