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How to Slice a Bagel into Two Linked Halves (2009)
- Whitespace 9y agoHere's George Hart's daughter Vi Hart making a Mexihexaflexagon, which is a kind of three-sided flat quesadilla: https://www.youtube.com/watch?v=GTwrVAbV56o https://www.youtube.com/watch?v=GTwrVAbV56o That family must have the best picnics!
- sp332 9y agoHere's a short series on math-based Thanksgiving foods. https://www.youtube.com/watch?v=F5RyVWI4Onk&list=PLaNzoFtkQ7rZo-HKloTHnhpimhfEzDlFl https://www.youtube.com/watch?v=F5RyVWI4Onk&list=PLaNzoFtkQ7... It's hard to know where to stop recommending Vi Hart projects, I find them consistently cool and fascinating, so I'll just mention her blog http://vihart.com/ http://vihart.com/ and Patreon https://www.patreon.com/vihart https://www.patreon.com/vihart
- kakarot 9y agoHexaflexagons are great and Vi Hart is great. Nice share.
- netcraft 9y agoah, I never put it together that they were related! That would be a fun family.
- tritium 9y agoThe manner of delivery is reminiscent of Steve “Protopod” Sutton’s [0] famous iced tea video. [1] [0] https://www.youtube.com/user/protopod https://www.youtube.com/user/protopod [1] https://www.youtube.com/watch?v=hSkT77010fE https://www.youtube.com/watch?v=hSkT77010fE
- earenndil 9y agoI prefer his other daughter, Vim Hart.
- needcaffeine 9y agoI didn’t know what I was getting into with that click, but now I’ve added bagels to our grocery list so I can do this.
- curiousGambler 9y agoBagel, lox, cucumber and cream cheese has become my new favorite thing lately (bonus points for a squeeze of lemon, capers or some red onion if those things are to be found). However, I of course have no bagels or bagel accessories on the one day I read about mathematically correct bagels :( So yeah, added to my grocery list too!
- geoffreyhale 9y agoThat was my dinner of choice throughout childhood. Love it still.
- troysandal 9y agoThis is the best article ever posted to Hacker News.
- pvorb 9y agoSharing stories like these with the world is what the world wide web was made for.
- deleted 9y ago[deleted]
- mabbo 9y agoI wonder if it's possible to repeat the process in such a way that you make a chain. I'm trying to visualize how but I'm not certain whether it could only make more links all attached in the same place.
- cwmma 9y agoyou'd need a very thick bagel
- rcthompson 9y agoI believe every link would be linked to every other link.
- delecti 9y agoNot necessarily. Just as you could take a chain and stack the links such that the holes lined up, with enough precision, and a strong enough baked good, you could cut the bagel such that there were a chain of linked rings.
- tritium 9y agoWell, if you cut the bagel according to this particular linked torodial method, to produce two links, you’d then be able to perform the traditional bagel slice on one of the linked halves, and that would produce a chain with three links... But deriving from a single original torus, a chain with an arbitrary or infinite number of links, whereby each individual link is bound to no more than two other links? I’ll have to think about that one...
- ihaveajob 9y agoExercise to the reader: How do you slice the bagel so that you can spread cream cheese continuously along both sides. In other words, can you make a Möbious bagel?
- jcoffland 9y agoLeave it uncut. It already has a continuous surface.
- deleted 9y ago[deleted]
- ihaveajob 9y agoI should document this and make it my first HN post.
- dumbfounder 9y agoDon't you have a job?
- jmgrosen 9y agoThis article is the best thing since sliced bread.
- mi100hael 9y agoOUT.
- hmate9 9y agoI never knew I needed this information. I’m gonna go buy some bagels now.
- hawktheslayer 9y agoMy team at work thinks of every excuse possible to get bagels. Recently for a birthday, a work anniversary, and being restacked into new cubes. But this is the best possible excuse for bringing in bagels again on Monday.
- Declanomous 9y agoThe resulting workers comp report when someone slices their hand is going to be really interesting.
- hawktheslayer 9y agoOf course if we could make a bagel cutter in the spirit of the popular bagel guillotine slicer that cuts a linked bagel we could be millonaires.
- phkahler 9y agoDon't share it. Just wait until the next batch comes in and then cut a few like this while no one is watching.
- kapauldo 9y agoHa! Awesome!
- tzahola 9y agoNow do it with a mug.
- ihaveajob 9y agoAll the pictures in that link already show a mug.
- delecti 9y agoA mug is topologically equivalent to a bagel or donut or torus.
- tzahola 9y agoT-topologically w-what?? I mean yeah, that was the point of my remark. To write something on topic as well: There was a fun little challenge on puzzles.stackexchange I think, which relied on the same construction as this article. I couldn’t find it, but it went like this: “You’re stuck on top of a tall building with nothing but a saw. There’s a ladder fastened to the side of the building, but it’s unfortunately not long enough to reach the ground; in fact it goes about half the height of the building from the top. Challenge is to get on the ground “safely”. You can cut into the ladder with your saw in any way you like and you can assume that the resulting pieces will be rigid, but won’t break under load.”
- chopin 9y agoAs far as I can tell this challenge would not require a twisted cut.
- yeukhon 9y agoIs it a sin to put pineapple on it? Someone please ask Professor Shewchuk (UC Berkeley) and Professor Demaine (MIT) to look at this! Perfect geometric problem for both of them.
- sizzzzlerz 9y agoClearly, a candidate for inclusion in one of the fine academic journals on mathematics. Or the Martha Bakes cookbook. Either way, bravo!
- qrbLPHiKpiux 9y agoVideo tutorial please.
- julioneander 9y agoThere's an addendum at the bottom of the page linking to a how-to video: http://www.youtube.com/watch?v=dN8AwGUaqDA http://www.youtube.com/watch?v=dN8AwGUaqDA
- joncrane 9y agoIt turns out there's a sequel! http://www.georgehart.com/bagel/knot.html http://www.georgehart.com/bagel/knot.html
- DrScump 9y ago"Waiter, my bagel has black magic marker all over it. I think I'll just have the omelette instead."
- jweather 9y agoNumberphile video on this topic, including 3d-printed examples of some higher-order slicings: https://www.youtube.com/watch?v=3_VydFQmtZ8 https://www.youtube.com/watch?v=3_VydFQmtZ8
- eschneider 9y agoI'd rather just have a mimosa. :/
- deleted 9y ago[deleted]
- gowld 9y agoI've tried never been able to achieve this with my hands and knives.
- tkahnoski 9y agoJust had a brief discussion at work about bagels that started with a complaint about how they're never sliced all the way through. After a couple minutes of back and forth an epiphany was realized that if they were pre-cut all the way through they'd get jumbled up and then we'd spend way too much time rifling through halves to find a matching one.
- macawfish 9y agoVillarceau circles! https://en.wikipedia.org/wiki/Villarceau_circles https://en.wikipedia.org/wiki/Villarceau_circles
- JacobHenner 9y agoVideo of the process: https://www.youtube.com/watch?v=2T5FrZl04JY https://www.youtube.com/watch?v=2T5FrZl04JY