Kaleidoscope
A kaleidoscope is an optical device that uses two or more plane mirrors and is capable of creating an infinite number of magical patterns ...
A kaleidoscope is an optical instrument that usually contains two or more plane mirrors,and it works by reflecting light. The mirrors are positioned so that their reflective sides face each other. By placing the mirrors at different angles to each other, it is possible to create beautiful symmetrical patterns. These patterns consist of fragments of glass or minerals of different colors in front of the mirror. Dichromatic glass is also often used. Dichromatic glass produces different colors, depending on the angle at which the light falls on it. By turning the kaleidoscope, it is possible to create an infinite number of patterns, each of which is unique.
Yakov Perelman, a famous Russian science author has written in his book "Physics for entertainment" - "Imagine that you have a kaleidoscope with 20 bits of glass inside and turn it to get ten new patterns every minute. How much time would you need to see all the patterns these 20 bits of glass could form? Even the wildest of imaginations would never provide the right answer. The oceans would dry, and the mountains crumble before you saw all. You would need at least 500,000 million years to see every figure produced! "