Neat, but academic, because as everyone undoubtedly knows slicing bagel into a Mobius strip is <i>far</i> more practical. Not only does it give you a surface for jam-and-buttering, but also keeps the construct in a single piece ensuring an unbeatable simplicity and predictability of the user experience. It's the same technique as in the article, but the knife needs to rotate at the half of its angular speed as it goes along bagel's diameter.
> It is much more fun to put cream cheese on these bagels than on an ordinary bagel. In additional to
the intellectual stimulation, you get more cream cheese, because there is slightly more surface area.<p>I believe this is winning on all fronts here.
This construction shows Villarceau circles[1], which are the nontrivial circle sections of a torus. This can be also seen on the POV raytracer hall of fame[2].<p><pre><code> [1]: http://en.wikipedia.org/wiki/Villarceau_circles
[2]: http://hof.povray.org/Villarceau_Circles-CSG.html</code></pre>
I have a number of friends who are middle and high school math teachers. I have asked them to demonstrate this for their students and report back on how utterly blown their students' minds are.<p>Stuff like this makes me wish I had continued on the path of becoming a math teacher myself rather than returning to the world of software.
The rest of George Hart's site is interesting as well, especially his encyclopedia of virtual polyhedra [1]. There is also a part 2 of "Mathematically Correct Breakfast" (this time a trefoil knot) [2], and his sculptures are worth looking at as well [3].<p>[1] <a href="http://www.georgehart.com/virtual-polyhedra/vp.html" rel="nofollow">http://www.georgehart.com/virtual-polyhedra/vp.html</a><p>[2] <a href="http://www.georgehart.com/bagel/knot.html" rel="nofollow">http://www.georgehart.com/bagel/knot.html</a><p>[3] <a href="http://www.georgehart.com/sculpture/sculpture.html" rel="nofollow">http://www.georgehart.com/sculpture/sculpture.html</a>
Previous discussions:<p><a href="http://news.ycombinator.com/item?id=982249" rel="nofollow">http://news.ycombinator.com/item?id=982249</a>
<a href="http://news.ycombinator.com/item?id=1234503" rel="nofollow">http://news.ycombinator.com/item?id=1234503</a>
<a href="http://news.ycombinator.com/item?id=1967930" rel="nofollow">http://news.ycombinator.com/item?id=1967930</a><p>This story has allotted a total of 656 karma, interesting.
I have tried these cuts a dozen times, never with success. What kind of knife/dough do you need to make clean cuts? 10 year olds can do it in two tries, why can't I?
Missed the Hacker News on this one ..<p>I know I'm not heavily karma'd and so my opinion counts for less, but this isn't the sort of thing I'm expecting on HN. This belongs over in Reddit (where I promise I'll still see it .. probably reposted a dozen times)