Look through this video to discover the 4 types of Klein Bottles!
Math Geek: From Klein Bottles to Chaos Theory, a Guide to the Nerdiest Math Facts, Theorems, and Equations
Where to Buy Klein Bottles
If you are fascinated by Klein Bottles, you can check out the website mentioned in the video: http://www.kleinbottle.com/
The website sells Klein Bottles under the name Acme Klein Bottles, made by Cliff Stohl.