Never Spill Your Drink Again

Invite your favorite mathematician friend over and pour his next drink from a Klein Bottle, and you'll have won his respect once and for all.

As mathematicians will know--and I'm sure your friend will go into great length and detail--a Klein Bottle is a mathematical construct hatched by Felix Klein a century and a half ago, when he imagined that two Möbius Loops could be combined to form a single-sided bottle with no boundary.

In practice, this means you have a surface that is wrapped in such a way that its inside is basically also its outside. It can't be done in our three-dimensional world, but you can get reasonably close.

With the glass Klein Bottles produced by Acme Klein Bottle, you can have such a strange construct yourself. With a Klein Bottle drinking glass you're really pouring your drink into your glass by pouring it on the outside of the glass, and a full bottle of wine is literally empty even if it's clearly full, because mathematically speaking the bottle can have no contents in the sense that it doesn't bound a volume.

I expect to purchase a Klein Bottle one day, primarily because I want to be able to accidentally spill my drink right onto the table outside of the Klein Bottle drinking glass, expecting the drink to appear inside of the glass nonetheless. I'm just hoping that the zero-volume property won't prevent me from drinking from the glass which, by definition, will always be empty.