A kaleidoscope consists of an eyepiece on the end of a viewing tube with multiple mirrors placed inside at an angle to each other. There are loose pieces of coloured transparent shapes (usually pieces of glass or beads) held between two glass discs at the other end.

A kaleidoscope operates on the principle of repeated reflection. When one looks through the eyepiece and the other end of the tube is rotated, the loose pieces of glass shift and are reflected, creating opportunities for ever changing, infinite mosaics that fills the entire visual field.