Kaleidoscope

A kaleidoscope is an optical instrument built from two or more reflecting surfaces angled to each other, usually enclosed in a tube, so that objects at one end are shown as a symmetrical pattern when viewed from the other end through repeated reflection. One end of the tube typically holds a cell of loose, colored pieces of glass or other transparent or opaque material, and rotating the cell moves these pieces to produce an ever changing pattern. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/