It was a large glass cage, or box - in fact a room.

"Then perhaps I'll learn about the glass cage the prince spoke of."

Whatever you've created is confined in that single glass cage.

During the trial, he was housed in a glass cage.

To protect the accused, they were made to sit in a glass cage during the trial.

"The glass cage doesn't have to fit just one, you know."

Or is it a hoax after all, and do we step out of the glass cage into death?

"Do you hate it here so much that you'd prefer a life in the glass cage?"

I heard that little spiel you gave these guys you've got in the glass cage.

The lobby of her building was a glass cage surrounding a guard.