You're not supposed to.
Nobody ever pays any attention to the exhibit cases in a museum.
You're not supposed to. But they have a life of their own, as I was to learn on a recent visit to the Freer Gallery of Art. Take those cases, for example. The old cases were beautiful, to be sure, lovingly designed more than 70 years ago by architect Charles A. Platt and Charles Lang Freer himself. Hidden within those legs were shafts that hoisted the glass bonnet up and down so that the curators could put things in or take things out.