I was thinking of getting a couch or something for my room, somewhere for guests to lounge around.
Fuck new couches. I now have a ball pit in my room.
I talked a little bit to Mike Machenry, who built a ball pit last year after reading my comic about it. The big problem with ball pits is that they’re expensive. Filling a room costs on the order of $4000, give or take. You can use this calculator (set up by relsqui of #xkcd) to find the cost for a given room. I’d use 64% for the packing efficiency — that’s about what I’ve found.
So given the expense, I didn’t fill my whole room — just an area the size of the bed, to a depth of a couple feet — and even that cost as much as a reasonable couch. The cost was as high as it was largely because Mike strongly recommended crush-proof balls, which allows for a lot more roughhousing but cost about twice as much as regular ones on eBay.
But it was totally worth it. After seeing how much fun it is to lounge around in it, we’ve decided to get together and build a larger one in the living room and throw parties there (though we want to solve the cleaning problem first in a scalable way). The day we put it up, we spent probably twelve hours, on and off, lounging around throwing plastic balls at each other. It’s totally worth it, and everyone’s excited about expanding it. It’s wonderful to be able to wake up and roll sideways, blanket and all, into a ball pit, and sink slowly down to the bottom. I’ve padded it with pillows and blankets to make it more fun to, uhh, wallow, or whatever the appropriate verb is for ball pits.
And before you jump to comment — over the last 24 hours we’ve completely exhausted all the balls-related innuendo, so you needn’t bother.
Here are some more pictures:
Abby, on the left, descends slowly into the balls. We never did find her again.
As Mike discovered, you can sort the balls pretty quickly by throwing only certain colors away from yourself.
Everyone I know seems to use Fujitsu Lifebooks. ❤ ultraportables.
To the above situation, we can only say:
xkcd 
comic #354?
i do the exact same thing.
only it’s like “….FIVE fingers!”
._____.
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Re #354, I used my automated money dispenser to transfer some virtual credits to the account of my global hand-held voice-and-text transceiver. This IS the future.
(I topped up my pay-as-you-go mobile via an ATM)
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Is it just me or is the search function searching a much smaller number of comics?
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I didn’t realise I had this (http://www.gnwco.com/washer.html) site open, so imagine my surprise as I’m closing windows until I see “Ball Washing Machine with Suction Unit” in the middle of my page..
Hilariously out of context.
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http://www.toysrus.com/product/index.jsp?productId=2476709#prod_prodinfo
Toys R Us has them by the 100. I went to the store today and felt a few of these, they seem to be of the crushproof variety and from what I’ve seen a little cheaper than some of the other ones I’ve seen online.
Any hints on where to find cheap balls are highly appreciated though at Zarloftheweird@gmail.com
Woo hoo for ball pits! You have inspired me!
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That looks like fun… 🙂
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You are officially my first celebrity crush.
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A Ruby web server (to compare with the Python one):
require ‘rack’
class App
def call(env)
[200, {}, ‘Hello World!’]
end
end
Rack::Handler::Mongrel.run App.new, :Port => 9292
Pretty slick.
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There’s a certain type of brain that is easily disabled…
and you posted that problem, that will haunt me for ever, on the day of my Quantum Mechanics final exam… damn you!!!
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Re the grid of resistors: I believe the answer to the question as posed be zero.
Proof:
We note that removing any given resistor can do nothing but raise the resistance between the two points. Thus we can start from an ’empty’ infinite grid, add as many specific resistors as we like, and have a system, the resistance of which bounds this infinite resistance above. Take N to be an arbitrary large integer. From the leftmost point, run a single chain N resistors long, and from there another chain K long upwards. From the rightmost point, run a chain K-1 upwards. Now link these two upward spikes with straight lines, each an effective resistor of N ohms.
Calculate the resistance of this system – it is (K-1)/N. But K is arbitrarily large, N/(K-1) arbitrarily small, so the resistance between those two points is zero. QED.
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Whoops, missed off a linear term. Don’t think it matters.
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ChrisJim, thanks. That was what I also thought as I was looking at it- that given an infinite field of ideal resistors of any value, the resistance between two points would approach 1/(infinity), or zero. Glad to have someone else verify that for me- I’m a mechanical engineer, not electrical.
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Whilst at IKEA a few weekends ago I happend upon possibly the best trash I have ever seen:
My god. SO MANY BALLS! You could have just TAKEN them! I don’t know what the plague vector possibilities are for these balls, obviously over-used in the IKEA children’s play area, but it would be worth it. All I thought about was that Sesame Street “1 2 3 4 5 6 7 8 9 10 eleven Tweeeeeeeeee – ELVE!” song.
These thousands of red balls are a party, art project or a hate crime waiting to happen.
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Tucatz, my argument as above doesn’t quite work. You have to just bound above the resistance between two points by p < 1 (quite easily you can get to ~0.720… with a ladder arrangement) and then say well, let’s apply the argument again but with the new upper bounds for each resistor in the chains in the ladder, which gives us a new, much lower upper bound… etc. etc. have a geometric sequence which tends to zero. I think that now works.
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I would just approximate it as the resistance of the four surrounding resistors connected to a conductor connected to the other four surrounding resistors. Should only be a few percent off.
So I’d calculate a half ohm resistance between any two points on the grid.
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hmm…. if you have a vacuum with sufficient sucking power, and if you rigged up two so that one of them is sucking, while the other is blowing, all you’d need is a sealed y valve and you have your very own “gravity gun” kinda like half-life… imagine the fun if you can make them portable!
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Seems like boshi’s estimate should provide a lower bound. In other words, the answer is not 0. I tried running a finite grid of 69*70 resistors and got .774 ohms. Convergence with increasing grid size seems rather slow.
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4/pi – 1/2
Hint: Boshi is correct in saying that there is a half-ohm resistance between any two points on the grid.
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The next instalment of my student loan is already earmarked for ball pit dorm room creation =)
For aaaaages I’ve wanted to have a ball pit in my room, but my parents always told me that was a silly idea… Now, having seen this, I plan on turning my box of a dorm room into a ball pit.
I figure I’ll only need about 1000 balls to fill quite a reasonable area of it… and based on my (probably very wrong) calculations, should only cost about £50-£60…
Suddenly it all seems very do-able…
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And NOBODY mentioned the OBVIOUS implications of the possibilities raptors have to HIDE in the ballpit?
I think that it is a very dangerous construction in this regard!
We need immediate establishment of counter-raptor monitoring efforts!
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Help a geek in Paris!
I’m going to survive in Paris. Due to leave from Bangkok next week.
Help me out! I’m desperate. What’s the translation of playpen ball in french?!?
I want to build the first XKCD inspired ball pit in Paris!
Guys it occurs to me that for a good fun the ball pit must be a good size and depth. Having it right away must be really cool but probably cost a lot of money.
I’m planning to start with just a little balls first and ask balls for christmas, eastern, my birthday and new year to all my friends and family. Hopefully, I’ll have a filled ball pit in about one year but it’s better than no ball pit at all!
Nico
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Having a ball pit in my house has been a dream of mine for as long as I can remember. I’ve always ALWAYS wanted one… that’s how I first learned of xkcd. A friend who (religiously) reads the comic showed me the ball pit comic, because Holy Crap that’s just like me.
I’m really happy that you’ve done this, it gives hope to me! I can’t wait to spend my days playing around, playing guitar hero, dancing, etc. in my very own ball pit =3
Although I need to read extensively about cleaning the ball pits…
And perhaps put some pouches on the wall next to the ball pit, so people can deposit their pocket items inside it… Because I will NOT search my ball pit for 3 cell phones, two wallets, and some lipgloss.
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I can’t help but wonder, is the comic really true? Do you really catch more flies with vinegar?
I don’t have flies around here, so I can’t do the experiment.
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A little comic I made at 4am this morning when I got bored before going to bed. It’s somthing which really needs to be taken into consideration! Seriously, I’m gonna end up locking myself out otherwise!
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oops, my link didn’t work! first time around!
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boshi: I do not think you are “only a few percent off”. It seems to me that as the distance between two points tends to infinity, so does the equivalent resistance between them.
Here is my argument: suppose you apply a non-zero potential at one point of the grid, and a zero potential at infinity. You can then rougly modelise the grid as a sequence of concentric circles so that all points lying on a given circle have the same potential, and there are roughly 2*Pi*N resistors, running in parallel, between the Nth and (N+1)th circle. (Yeah, I know it is somewhat problematic to draw circles on an integer grid. You could replace circles by squares, but then nothing guarantees that all the points will be at the same potential. However, I think that if you look at the grid at a large scale, it behaves roughly the same as a continuous sheet of metal.) In this case, the resistance between two consecutive circles is roughly 1/N (multiplied by a constant), so the resistance between the center and the Nth circle is roughly Sum from 1 to N of 1/N, that is, ln N.
Now if you take two points on the grid 2N squares apart, you can provide a lower bound to the resistance by modelising the grid as two disks of radius N centered on the two points, connected by an ideal conductor. This suggests that the resistance grows as the logarithm of the distance.
Ryan: Maybe you mean “between any two neighbour points”? This is what I found, too, but I do not see how to deduce the answer for two points that are farther apart.
Actually, there is a very simple proof that the resistance between two neighbour points (let’s call them A and B) is 1/2 Ohm. Take an ideal current source of 1 Amp, and connect one end of it to A and the other end to the ground. Then for obvious symmetry reasons, the current through the resistor connecting A to B will be equal to 1/4 Amp, so the voltage between A and B will be 1/4 V.
If you do the same thing for B but with opposite polarity, the current between A and B will still be equal to 1/4, and the voltage will still be 1/4.
Now it is clear that the equations involved are linear, so connecting a current source of 1 Amp between A and B is equivalent to sending at the same time 1 Amp from the ground through A and 1 Amp from B to the ground. The voltage between A and B is then equal to the sum of the two voltages, that is, 1/2 V, QED.
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http://www.huggingmattress.com/index.php
just read the URL, you will understand
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that would be awesome
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tikiloungelizard: Are you SERIOUS? What kind of small minded simpleton would honestly be offended by the word ‘fuck’, used once in a non-threatening way?
How could that POSSIBLY upset you? You may choose not to use such language, but how are you ANY worse off if somebody uses a word like fuck? Do you not have the strength of mind to ignore 1 single word?
Face the facts – The part of the brain that controls cursing, yelling and crying is the exact same part of the brain that causes a dog to yelp if you stand on his tail. Its a natural reaction that can be scientifically explained, why would any creator make this part of your brain, and then expect you not to use it?
Let me guess, you would also be offended if somebody mentioned evolution?
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‘GetaPair’, if you read the post, tikiloungelizard is talking about eir sister, not eir own reaction. I can imagine a person as young as 8 enjoying XKCD – and if I had (say) an 8 year old sister, I might well not show them media containing swearing.
Face the facts – not everyone uses language in the same way you do (and some people have self-restraint enough that if they don’t wish to swear, they don’t).
Creator? Evolution? What are you rabbiting on about?
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The living group where I spent the first two years of my undergraduacy had a tradition of getting the used foam from the Boston Children’s Museum. We filled a room with the pieces and had our very own foam pit. That might be a cheaper route to equivalent fun, for those on a budget.
In other news, I will never ever say that Randall has an easy job.
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Guess who just got a 23,000 ball pit?
http://blog.last.fm/2007/12/21/blogging-from-the-ballpit
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…and it is awesome 🙂
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@Hi?u ??c Hoàng
>> It strikes me that Google should do this somewhere on their campus (if they haven’t
>> already…?) It would fit their whole motif pretty well 🙂
> @Charlie: Google has a ballpit, really,
> http://steve-yegge.blogspot.com/2007/02/nooglers-view-of-google.html
Nice! Somehow I’m not surprised.
I’ve actually gone and interviewed at Google since I posted that. Didn’t see the ballpit, and didn’t know that Randall was going to be giving a talk there TWO DAYS LATER. If I’d known that, I’d have worked it so I was there to see it. One of the first things I noticed when walking into building 47 though was that the same “cake” strip was taped to the front desk. I was looking at it as I sat in that massage chair waiting for the recruiter.
That must’ve been awesome having a “I’d like to visit the campus” turn into a “We want you to speak! Your first interaction with brilliant, famous compuer scientists will be when one introduces you and two more approach the microphone to ask _you_ questions.”
I asked about getting a look around while I was there. They were fine with that, and I got a quick look around during lunch.
Oh, to have a great webcomic to your name! You have captured the geek zeitgeist my friend.
I’m still waiting to hear back about the interview though. Argh. The people I work with now would just not understand these things the way so many googlers obviously do. I feel that these googlers are my people.
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@Hieu Duc Hoang (roughly)
>> It strikes me that Google should do this somewhere on their campus (if they haven’t
>> already…?) It would fit their whole motif pretty well 🙂
> @Charlie: Google has a ballpit, really,
> http://steve-yegge.blogspot.com/2007/02/nooglers-view-of-google.html
Nice! Somehow I’m not surprised.
I’ve actually gone and interviewed at Google since I posted that. Didn’t see the ballpit, and didn’t know that Randall was going to be giving a talk there TWO DAYS LATER. If I’d known that, I’d have worked it so I was there to see it. One of the first things I noticed when walking into building 47 though was that the same “cake” strip was taped to the front desk. I was looking at it as I sat in that massage chair waiting for the recruiter.
That must’ve been awesome having a “I’d like to visit the campus” turn into a “We want you to speak! Your first interaction with brilliant, famous compuer scientists will be when one introduces you and two more approach the microphone to ask _you_ questions.”
I asked about getting a look around while I was there. They were fine with that, and I got a quick look around during lunch.
Oh, to have a great webcomic to your name! You have captured the geek zeitgeist my friend.
I’m still waiting to hear back about the interview though. Argh. The people I work with now would just not understand these things the way so many googlers obviously do. I feel that these googlers are my people.
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I loved this. The epitome of cool
okay! so i didn’t have anything clever or interesting to contribute sue me ha
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