kaleidoscope

noun

1. an optical instrument in which bits of glass, held loosely at the end of a rotating tube, are shown in continually changing symmetrical forms by reflection in two or more mirrors set at angles to each other.
2. a continually changing pattern of shapes and colors.
3. a continually shifting pattern, scene, or the like: The 1920s were a kaleidoscope of fads and fashions.

noun

1. an optical toy for producing symmetrical patterns by multiple reflections in inclined mirrors enclosed in a tube. Loose pieces of coloured glass, paper, etc, are placed between transparent plates at the far end of the tube, which is rotated to change the pattern
2. any complex pattern of frequently changing shapes and colours
3. a complicated set of circumstances

n.

1817, literally “observer of beautiful forms,” coined by its inventor, Scottish scientist David Brewster (1781-1868), from Greek kalos “beautiful” + eidos “shape” (see -oid) + -scope, on model of telescope, etc. They sold by the thousands in the few years after their invention, but Brewster failed to secure a patent.

Figurative meaning “constantly changing pattern” is first attested 1819 in Lord Byron, whose publisher had sent him one. As a verb, from 1891. A kaleidophone (1827) was invented by English physicist Sir Charles Wheatstone (1802-1875) to make sound waves visible.