Fiberscope

A low quality fiberscope observing the inside of an antique clock mechanism. Note how individual fibers are discernable, as each fiber only relays one part of the image.

A fiberscope is a flexible optical fiber bundle with a lens on one end and an eyepiece or camera on the other. It is used to examine and inspect small, difficult-to-reach places such as the insides of machines, locks, and the human body.