# Four Dimensional Hats: A Visual Wonder!

[Image courtesy of Brilliant.org.]

The mobius strip is one of the simplest objects in the world, and yet, the most mind-bending. If you take a strip of paper, add a single twist, and tape the ends together, you transform a two-sided object into a single-sided object. It becomes one continuous surface.

(We’ve discussed the concept briefly in the blog before, but in bagel form.)

But did you know that you can take that idea a step further and end up with this?

[Image courtesy of math.union.edu.]

This is a Klein bottle, an object with one continuous surface. If you trace a path along the surface, you will traverse from the “inside” to the “outside” and back again without breaking stride.

Yes, the word “bottle” is a bit of a misnomer, since this won’t actually hold any liquids; they would just flow along the surface, going “inside” and back “out” without pooling anywhere. This is a result of a mistranslation, as the German word “flache” (surface) was translated as “flasche” (bottle).

This limerick sums up the Klein bottle nicely:

A German topologist named Klein
Thought the Mobius Loop was divine.
Said he, “If you glue
The edges of two,
You get a weird bottle like mine.”

[Image courtesy of Pinterest.]

Although the Klein bottle can’t quite exist as a three-dimensional object — since the object has to pass through itself, which can only happen in four dimensions — we can come close enough to create some impressive approximations, like the glass “Klein bottles” pictured above.

YouTuber and physics student Toby Hendy has even managed to create a technique to knit yourself a Klein bottle hat! Check it out:

Although it’s not an optical illusion, it’s still a visual puzzle for the eyes and the mind, one that has captured the imaginations of mathematicians, artists, and many others throughout the years.

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# Pi Day and Puzzly Foods!

It’s Pi Day — March 14th, a.k.a. 3.14 — and as one of the nerdiest days of the year, we happily celebrate it here at PuzzleNation.

A friend of the blog asked if we’d be celebrating Pi Day with some apple pi pie, and sent me this video from YouTuber Rosanna Pansino:

That gave me an idea. Why not dedicate an entire blog post to puzzly foods?

Naturally, I have to start with some Rubik’s-inspired foods. It’s blocky style lends itself to foodly imitations, and in previous blog posts, we’ve shown off both Rubik’s fruit salads (like the one above) and Rubik’s cakes.

And while we’re talking about cakes, that brings me to another puzzly product that is easily replicated in food form: Tetris.

These cupcakes adorned with Tetris pieces are a perfect puzzly dessert, and a simple way to marry puzzling and food.

But if you’re looking for something a bit more challenging and involved, check out this Tetris bento box, crafting Tetrominoes into blocky veggies on a bed of rice for lunchtime enjoyment!

And puzzly foods only get more creative and complicated from here. Let’s talk about bagels.

Yes, there is a way to cut a bagel to leave two interconnected pieces. In fact, there are several ways to cut a bagel allowing for a more mathematical eating experience! It’s the mobius bagel!

But if you’re looking for the puzzliest food I can find, look no further than the Churroduo: two interlocked churro pyramids.

I think this excerpt from a write-up on Geekologie sums up the appeal of the Churroduo nicely:

Still, the best thing about the Churroduo is that you don’t have to feel bad about eating the whole thing, because you only ordered ONE of something, you can’t help that it’s actually like twelve churros stuck together.

Do you have any examples of puzzly foods that I missed? Are you celebrating Pi Day in a puzzly way? Let us know in the comments section below! We’d love to hear from you!

Happy Pi Day, fellow puzzlers and PuzzleNationers!

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