HN Theater @HNTheaterMonth

⬐ hgibbs

Funny story. I saw this video yesterday morning, about an hour before my topology exam. One of the questions involved calculating the Euler poincare characteristic of a 3 fold sum of RP2. Unfortunately, I had forgotten the formula for the case of m-fold sums of RP2 but I knew that it was linear in m and that the Euler poincare characteristic of RP2 was 1. Luckily, I remembered a Klein bottle is homeomorphic to the 2-fold sum of RP2. Having seen this video and knowing the cell complex structure of a mobius band ended up being enough for me to derive the answer.

⬐ copperx

I want to be like you when I grow up.

⬐ hgibbs

I had a really bad day. Cheers man you have no idea how much that means to me.

⬐ None

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⬐ waqf

You could also have used the fact that S² is homeomorphic to the 2-fold sum of S².

⬐ HCIdivision17

Just because there has to be an obligatory link to his phenomenal website:

http://www.kleinbottle.com/

Cliff Stoll has to be one of the most genuine and wonderful mad engineers out there. His work is just one gem of brilliant hackery after another.

⬐ dbarlett

I highly recommend ordering one. The checkout process, packaging, and invoice are almost as good as the bottle itself.

⬐ david-given

Don't forget the guarantees!

http://www.kleinbottle.com/guarantee.htm

⬐ jws

And remember the inventory is stored in the crawl space under his house and he uses tiny robots he built himself to go in and pull the inventory out.

⬐ vermontdevil

And his TED video too - great stuff.

https://www.ted.com/talks/clifford_stoll_on_everything?langu...

⬐ lifeformed

Is a cut glass edge not sharp? It was hard to watch him run his finger along the edge like that.

⬐ Natsu

That depends on whether it has been seamed or has edgework. It's incredibly sharp if nothing has been done to it, enough so that merely touching glass edges can cause cuts. Glass is normally seamed before tempering, but that doesn't leave it perfectly smooth either. I've gotten glass splinters from it, along with finding edges that didn't get seamed well, though most sharp edges will break in the tempering furnace (this is why you seam glass prior to tempering). Glass splinters are as horrible as you might imagine and can take weeks to work themselves out, as well as being ridiculously hard to see.

So yeah, I don't recommend the practice if you're not sure, but it may be okay for glass that has had edgework done as this glass gets polished smooth, whereas tempered glass is probably okay, but not always safe.

EDIT: Looks like it's blown glass. No, that's not very safe.

⬐ DHJSH

I expected his finger to be bleeding after he picked it up. I'm wondering if it's just a property of the diamond saw, or he likes to live dangerously.

⬐ DannyBee

Having a cut a ton of stuff with diamond saws, the edge they leave is very abraded, and rarely sharp.

This is not surprising, since it's basically like cutting it with 60-180 grit sandpaper

⬐ Natsu

You're probably right that the edge isn't so sharp, though I note that his finger was higher above it than it looked, but I wouldn't underestimate glass splinters.

Those really suck.

⬐ newman314

You should also watch the related video about how he stores Klein bottles under his house. It's fascinating.

https://www.youtube.com/watch?v=-k3mVnRlQLU

⬐ te

If someone does a remake of Back to the Future, Doc Brown should have a robotically-operated klein bottle warehouse under his house.

⬐ jbpetersen

Cliff is a wonderful, wonderful human being. He once did a series of free physics classes for middle schoolers in his garage. Learned how to measure the speed of light from him.

⬐ copperx

He emits light?

⬐ tbabb

Sometimes I wonder what future, more evolved humans will be like. What traits will be emphasized?

I hope they look like this guy. Insatiably curious, extremely intelligent, endlessly productive, and effusively happy.

⬐ jlebar

I bought a small klein bottle from him some time ago, and it was worth it just for the papers it came with. Hours of laughter... So good.

⬐ gloves

Never seen this guy before, but I love him! So enthusiastic.

⬐ ubersync

How did I not know about Cliff Stoll until today?

⬐ baldfat

Watch the video that is an hour long about him catching a hacker in the early 1980s

⬐ ubersync

I already did. It is awesome. This guy has so much energy.

⬐ Magi604

I want a diamond saw.

⬐ JshWright

I love Cliff Stoll so much... I hope one day to be as passionate about _something_ as he seems to be about everything...

If you haven't read The Cuckoo's Egg, I'd highly recommend it. It details his experience tracking down one of the first "hackers" back in the 80's, when he was a sysadmin for Lawrence Berkeley National Laboratory.

⬐ smoyer

I've got an old copy and have read it through twice ... and it's currently sitting in my bosses office waiting for him to read it.

I'd say that it's one of my two favorite non-fiction books (the other being "Surely You're Joking Mr. Feynman").

⬐ jrk_

> I hope one day to be as passionate about _something_ as he seems to be about everything...

The last time I've been so passionate about something was when I was around 10 or 12. Since then I've trained myself to be (and act) not so passionate anymore, because it'll make you look like a weirdo to most people. However, it brought me to a point where it's hard for me to get excited about anything at all, not to speak of expressing it properly...

⬐ smrq

That's amazing-- I had both read that book and seen a few of his appearances on Numberphile, but I never connected the two.

This same phenomenon happened to me not long ago actually, when I discovered that two of my all-time favorite bands shared a guitarist (Greg Edwards of Failure and Autolux). Is there a term for discovering that two people you know of are actually one and the same? I find it to be a rare pleasure-- you can almost feel the mental connections linking themselves together, and afterwards the world feels like a smaller, more logical place.

⬐ teh_klev

I read it when it was first published, twice in the same week I bought it. It's was a really good story. Sadly I lost my copy, possibly due to lending it to someone.

⬐ Ductapemaster

It really is a fantastic story. I can't recommend it enough.

⬐ sp332

There's a one-hour long NOVA episode about that story. https://www.youtube.com/watch?v=EcKxaq1FTac

⬐ _qbww

Thanks for sharing that. I had seen the Klein bottles under his workshop video awhile back, but I had no idea how deep this rabbit hole went.

⬐ saboot

I'm only three minutes in and I'm already loving this. Thanks for sharing