But there was something else, too: hundreds of hollow spheres and filaments.

NEWYORKER: The Martian Chroniclers

But what if that, too, was a hollow promise, from a hypocrite who repented only after, who promised submission but really only wanted a reprieve?

NEWYORKER: Good People

For instance the light pipes currently suffer from too much light loss unless they are kept short, and there were complications in creating completely enclosed hollow areas.

BBC: Disney develops 3D-printed lighting for toys