A wildly impractical but totally beautiful 'two-dimensional' wine bottle has be launched for sale.
The Klein bottle was first conceived of in 1882 by German mathematician Felix Klein.
Its mind-bending design is essentially two Mobius strips connected together, turning it into a "non-orientable surface" in which in the inside is indistinguishable from the outside.
But where a Mobius strip is a surface with boundary, a Klein bottle has no boundary (for comparison, a sphere is an orientable surface with no boundary)
The bottle has now been turned into a real product, but its makers apologetically explain that it's very hard to use since the air inside has nowhere to go when you pour liquid into the spout.
"The Wine Bottle Klein Bottle is difficult to fill with wine, because of vapor-lock. As you pour water (or wine) into it, there's no place for the air to go. So the wine is trying to go down while the air is trying to go up the spout. Result is slow filling.
Pouring wine out is equally frustrating… Not only are these difficult to fill and empty, but cleaning them is a real challenge. Since there's little air circulation within the Klein Bottle, moisture doesn't evaporate. Worse, you can't reach in with a towel. So you'll need to dry the interior surface using alcohol. I've had good luck with a pair of small magnets wrapped in cotton cloth."