Kaleidoscopes create symmetrical patterns by reflecting light between angled mirrors inside a tube.

The longer version

Two or three mirrors joined at an angle create a wedge, and light bouncing between them generates a chain of reflected copies of whatever sits at the far end. The copies tile around a central point, so loose coloured fragments read as a perfectly balanced rosette.

The instrument was patented in the nineteenth century by a Scottish inventor studying polarized light, and it became a parlour toy almost immediately. Changing the angle between mirrors changes the number of repeats. Turning the tube reshuffles the fragments, and because the pattern is built from reflections it never repeats exactly.

Where this entry sits

These facts explore how light behaves and how human eyes turn it into the colors we see. Along the way you meet rainbows, prisms, mirrors, shadows, lasers, and optical tricks that fool our vision every day. The full list sits on the Color and Light page, where every entry is listed in order.