(Thanks to Google Images for picture)
Did you ever have a kaleidoscope as a child? You know, one of those tube-shaped toys with loose bits of colored material (such as glass or plastic) that changed symmetrical patterns when you looked inside one end and twisted the collar.
In 1814 Sir David Brewster was conducting experiments with light reflection. Several experiments and modifications later, he placed the reflecting panes in a draw tube with a concave lens to distinctly introduce surrounding objects into the reflected pattern. Voila! The kaleidoscope.
Most handmade kaleidoscopes are now made in Russia and Italy, intended as children's toys. Craft galleries sometimes carry handmade pieces that display fine craftsmanship.
Interested in trying your hand at making your own? YouTube has a video of instruction. (https://www.youtube.com/watch?v=Z2TDK_OQWU0)
The word kaleidoscope can also mean a mixture of many different things, like the back room in my house. It's too small to be a bedroom and too far from a heating/cooling source to be comfortably lived-in. So it has become an everything-that-doesn't-have-a-place room.