**I’ve had some fun playing around with old CDs and CD cases recently.**

In addition to demonstrating Cavalieri’s principle both with discs and their cases, I’ve found some other mathematical uses for these objects.

Here I’ve used a stack of cases to demonstrate the difference between some geometric solids.

On the left, we have a right rectangular prism. Give that prism a slight push in a direction perpendicular to a side and you get an oblique rectangular prism.

And if you give that original prism a push along a diagonal of the base, you’ll get one of my favorite geometric objects, a parallelepiped. It may not be the perfect parallelepiped, but I’ll take it!

I was hoping I could expand the picture enough to read the labels. Maybe math-lovers have the same taste in music? Haha, but great post regardless.

You can make out some of the titles in this image.

I already received a thumbs-up for the Black Sabbath album.