Klein bottle bottle opener

Yes, it's $72. But this 3-D printed metal sculpture/bottle opener is fantastic. And so is its marketing copy.

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.

Read the rest of the product description and, you know, maybe buy the bottle opener, too. If you're feeling spendy.

Via Cliff Pickover


  1. That copy suggests something false, namely that a wild sphere could potentially fail to divide 3-space into two disconnected regions. The Jordan-Brouwer separation theorem states that *any* sphere divides 3-space into two disconnected regions. 

    However, if the sphere is wild, those regions might not be simply connected (that is, there might be a loop in 3-space which doesn’t intersect the sphere, but which can’t be shrunk to a point without passing through the sphere).

  2. Anyone else read the headline and think it meant something to the effect of “a device for opening Klein bottles”?

        1. A Klein bottle has no inside of any kind. It’s literally impossible to contain anything in a true 4D Klein bottle. Similarly to how it’s impossible to write on the “rear surface” of a Möbius strip.

          At least that’s how I understand it. And there’s a strong chance that I’m just very wrong, and sound like a fool. Feel free to correct me with a source if this is the case.

  3. I totally want one. 

    Not at that price though. At this point 3-D printing for  tchotchkes is quite absurd. I’ll wait for the die-cast version made for cents on the dollar soon to be sold at my local science museum gift shop.

    1.  I don’t think you could make an ordinary mold for that. Lost wax  might work, but how would you make the wax bit?

  4. I’ve been keeping an eye on 3-D printing for years, and it seems like only yesterday it was possible to buy a kit of parts to assemble into a printer (Makerbot?) for about $500. Does this exist any more?

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