Review on Enhancing Learning with Optical Photography Triangular Teaching Education by Melvin Goerge

I bought these to teach my 6 year old daughter the principles of light and how rainbows are formed. The two triangular ones form a rainbow with a ray of sunshine falling through the windows, she had a lot of fun with that. As a bonus, the glass ball rolls pretty smoothly across our hardwood floor and she had fun with it too :) She then used the square block to build Elsa's frozen castle with the rest of her Legos. I think this "toy" is money well spent compared to plastic that often has to be thrown away.