Duoprism

A duoprism is like putting two prisms together to make a new shape. Prisms are things that bend light and make it look rainbow-y.

Imagine you have two triangular tubes made of glass. When you look through them, everything is split up into lots of different colors. Now, let's put them next to each other in a special way so that they make a new shape. When you look through this new shape, the light is bent and split up in even more cool ways!

So a duoprism is just two prisms combined into a new cool shape that can do even more tricks with light!