For the telescope build in question, [Unnecessary Automation] needed a concave mirror. ... Perhaps filling the sheet with a hot relatively dense liquid like molten wax to form the parabolic shape.

Like acoustic mirrors, the microphones use a parabolic dish to reflect sound from a specific direction into the mic at the center (the U.K.’s war devices were technically spherical, not ...

Eversley’s motion produced a concave parabolic hollow in the quivering Jell-O that turned out to be his first artwork, though he didn’t know it at the time.