Ever since the Obama Presidential Center began rising out the historic grounds of Jackson Park, its Museum Tower — the campus’ most visible structure — became a riddlesome, what-the-heck-is-this kind of a building. And there was a reason for this. In a city of tall, glassy skyscrapers, the Museum Tower is shrouded in granite and virtually windowless. While the best of Chicago’s parks buildings attempt to blend in with their landscapes, the stocky, square-jawed 225-foot building at 6101 S.