Here are some prisms for maths education. I used these to teach the calculation of the surfacearea and volume of prisms. 

They are sorted by difficulty/colour from green - blue - yellow - red. The white ones are for the introduction to the topic. Later the difficulty can be personally chosen by colour. 

Some prisms are available in multiple colours. On the lower difficulty the prisms are held together by magnets, so that there is an inbuild help.