Crews are putting the finishing touches on the Obama Presidential Center ahead of the official public opening in Chicago on Juneteenth. But the unusual design of the $850 million campus _ particularly a 225-foot gray high rise _ has provoked a debate in the city celebrated as the birthplace of the modern skyscraper. For some, it’s a jarring choice in Barack Obama’s hometown, particularly after a grueling battle over its location in a lakefront park surrounded by classical style buildings. To others, it’s a bold way to add to Chicago’s iconic skyline.