Buildings come and buildings go. And the ones that stay with us for a long time rarely stay the same. Often we no longer notice additions and alterations undertaken decades ago, even when they're executed in a variety of styles and voices. A number of people have raved about the gorgeous auditorium in the equally stunning Public Service Building, 231 W. Michigan St., but not a single one thought to mention that this space is an art deco gem inside a beaux arts/classical revival masterpiece.