A Klein bottle is "a closed surface with only one side; formed by passing one end of a tube through the side of the tube and joining it with the other end." Pictured above is a bottle opener shaped like a Klein bottle. It was made by Bathsheba Grossman, who explained:
The problem of beer That it is within a 'bottle', i.e. a boundaryless compact 2-manifold homeomorphic to the sphere. Since beer bottles are not (usually) pathological or "wild" spheres, but smooth manifolds, they separate 3-space into two non-communicating regions: inside, containing beer, and outside, containing you. This state must not remain.
A proposed solution Clearly the elegant course is to introduce a non-orientable manifold, which has one side and does not divide 3-space. When juxtaposed with the beer-bounding manifold described above, it acts to disrupt the continuity thereof, canceling the outdated paradigm of distinction between interior and exterior. This enables the desired interaction between beer and self.
Link via Nerdcore | Photo: Bathsheba Sculpture
You'll notice both comments before mine were about the fact that this product is overpriced for them. I simply pointed out why. Call it marketing if you like, but the writing is pretentious and in my opinion, ineffective.
Most of the money spent on most of the gadgets that you own was spent on "hooha". It's called marketing.
Although marketing makes us want things that we don't really need or would have wanted in the first place, there is nothing intrinsically wrong with paying what it is worth to you rather than the absolute minimum it could have sold for.