A kaleidoscope is a circle of mirrors, typically inside of a tube, with colored objects at one end. As the tube is rotated, light entering the end of the kaleidoscope strikes the colored objects and creates a symmetrical pattern in the mirrors.
When the USS Enterprise-D pursued the shuttlecraft Goddard through a gravity slingshot, Captain Jean-Luc Picard likened the experience to a kaleidoscopic roller coaster ride. (Star Trek novel: Engines of Destiny)
See Also
Kaleidoscope article at Wikipedia, the free encyclopedia.