What is a kaleidoscope? State the principle on which it is based

What is a kaleidoscope? State the principle on which it is based.

A kaleidoscope is an optical instrument usually with three reflecting surfaces ( mirrors) tilted to each other in an angle so that it forms a triangle crosssection. Objects on one end of the mirrors are seen as a regular symmetrical pattern when viewed from the other end, due to repeated reflection.

The reflectors (or mirrors) are usually enclosed in a tube, often containing on one end a cell with loose, colored pieces of glass or other materials to be reflected into the viewed pattern. Rotation of the cell causes motion of the materials, resulting in an ever-changing view being presented.

when two mirrors are inclined to each other by an angle θ and an object is placed in between mirrors, number of images seen is (360/θ).
This is the basic principle behind the kaleidoscope