Although light travels only in straight lines, it can be made to bend around curves and angles using optical fibres. These are bundles of very thin strands of exceptionally clear glass. The fibres are treated so that their outer surface reflects light. When light is shown in one end of the bundle it passes along the fibres, reflecting from the sides as they curve and eventually emerging at the far end.
Optical fibres carry electronic signals to computers, and they are increasingly used in telephone lines. Optical fibres are very useful in medicine to diagnose disease. A flexible fibreoptic probe can be inserted into the body to view the internal workings of an organ.
Picture credit: google
