## 0356: "Nerd Sniping"

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### Re: 0356: "Nerd Sniping"

I have friends that read xkcd and since they found this particular one I've seen papers that have confusing problems on them... I think I'm being conspired against...
This IS my other signature
Zalde Ocga

Posts: 8
Joined: Thu Apr 28, 2011 1:41 am UTC

### Re: 0356: "Nerd Sniping"

Made a nerd sniping ripoff for my hobby webcomic when I was bored the other night:
http://brajn.org/comic/qr-code-sniping

Thanks for the inspiration!
mclemme

Posts: 1
Joined: Sun Jun 19, 2011 12:27 pm UTC

### Re: 0356: "Nerd Sniping"

I got nerd sniped.
I want to tell the story.

I was a Yucca Mountain Information Center with a friend.
http://en.wikipedia.org/wiki/Yucca_Moun ... repository

There is a great deal of information there. I was reading what I could. My friend was reading the math. It was hard for him. Some of it took him a while. Most of it was so far over my head that I did not need to duck.

Then, it happened. We walked around a corner together. There it was. A pedestal with a bowl on top. One nice bowl that was placed so that the labels could be read by a person that walks around that corner.

SPENT NUCLEAR FUEL ROD

We both stopped, dead in our tracks. There were some seconds that went by. Twenty seconds. "We are dead." Was said.
I don't know who said it. It could have been either one of us.

I moved first. I knew if that shit was real, then, we were dead. I wanted to look at it.

I walked over to the bowl, picked one up and said, "It's light."

He said, "It's light?"

"Yep.'' I lifted it to show him.

He ran over to that bowl. It was so funny.
I wonder; Do they have a camera on that bowl? How long different people stay frozen would be interesting.
The audio would be fun too. "Look Ma! They are giving away Fuel Rods!"

Do people ever read the label and run away? That is funny. Do they think that they have been exposed?

What I do know is they 'GOT' us. We were two Nerds that were down.

It was, just, too fucking interesting for about twenty seconds or so.

I know that this post may ruin the fun for those guys. The number of people that will go to Yucca Mountain, that also read this comic? That overlap may be quite high. Hey! If, the guys that did that practical joke read this comic, then; You Got Us!

We laughed a lot. That was one of the funniest things we saw on that Road Trip. We saw a great many funny things. That bowl of spent nuclear fuel rods was the funniest.

We talked about tourists as a fix for the fuel rod problem. It gave us something to think about for a while. Human nature being what it is. It might work.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

Those that want to Know, Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

Posts: 2403
Joined: Sun Sep 12, 2010 4:44 am UTC

### Re: 0356: "Nerd Sniping"

addams wrote:I got nerd sniped.
I want to tell the story.

I was a Yucca Mountain Information Center with a friend.
http://en.wikipedia.org/wiki/Yucca_Moun ... repository

There is a great deal of information there. I was reading what I could. My friend was reading the math. It was hard for him. Some of it took him a while. Most of it was so far over my head that I did not need to duck.

Then, it happened. We walked around a corner together. There it was. A pedestal with a bowl on top. One nice bowl that was placed so that the labels could be read by a person that walks around that corner.

SPENT NUCLEAR FUEL ROD

We both stopped, dead in our tracks. There were some seconds that went by. Twenty seconds. "We are dead." Was said.
I don't know who said it. It could have been either one of us.

I moved first. I knew if that shit was real, then, we were dead. I wanted to look at it.

I walked over to the bowl, picked one up and said, "It's light."

He said, "It's light?"

"Yep.'' I lifted it to show him.

Excellent!

I've got a bucking bar made of 95% tungsten, 5% nickel. It's a section of rod about 2 to 2.5 inches in diameter and about the same length. I have no use for a bucking bar, I got it to show people because it's so unexpectedly dense it's fun to handle. I'd prefer iridium or even platinum, but I can't afford five pounds of either of those substances.

It's clearly a section of a rod, though. I wonder if I could get anyone to believe it's part of a spent nuclear fuel rod. I suppose it might help if I warm it up to around 120 F first, just for effect. "I lucked out, it's not quite fully spent!"
webgrunt

Posts: 103
Joined: Thu Apr 21, 2011 4:04 pm UTC

### Re: 0356: "Nerd Sniping"

webgrunt wrote:
addams wrote:I got nerd sniped.
I want to tell the story.

I was a Yucca Mountain Information Center with a friend.
http://en.wikipedia.org/wiki/Yucca_Moun ... repository

There is a great deal of information there. I was reading what I could. My friend was reading the math. It was hard for him. Some of it took him a while. Most of it was so far over my head that I did not need to duck.

Then, it happened. We walked around a corner together. There it was. A pedestal with a bowl on top. One nice bowl that was placed so that the labels could be read by a person that walks around that corner.

SPENT NUCLEAR FUEL ROD

We both stopped, dead in our tracks. There were some seconds that went by. Twenty seconds. "We are dead." Was said.
I don't know who said it. It could have been either one of us.

I moved first. I knew if that shit was real, then, we were dead. I wanted to look at it.

I walked over to the bowl, picked one up and said, "It's light."

He said, "It's light?"

"Yep.'' I lifted it to show him.

Excellent!

I've got a bucking bar made of 95% tungsten, 5% nickel. It's a section of rod about 2 to 2.5 inches in diameter and about the same length. I have no use for a bucking bar, I got it to show people because it's so unexpectedly dense it's fun to handle. I'd prefer iridium or even platinum, but I can't afford five pounds of either of those substances.

It's clearly a section of a rod, though. I wonder if I could get anyone to believe it's part of a spent nuclear fuel rod. I suppose it might help if I warm it up to around 120 F first, just for effect. "I lucked out, it's not quite fully spent!"

What fun! I would like to see your bucking bar. I like that sort of thing.
Yes. For persons that know about the heat then warming it up would help the practical joke. It makes a great practical joke.
When I was a young person, humans were still working on what radioactive materials were. There was Uranium being mined in Eastern California. I held some. I did not hold it long. There were adults teasing me.
I was asked what I thought it was. I said, "It is a rock that has been in the sun." The men laughed at me. The rock felt like a rock that has been in the sun. It really is warm to the touch.
I would love to help you with your practical joke. You have a small problem. If, the audience knows nothing about nuclear physics, then, the joke will fail. You may need to educate your audience a little. Tell a friend or co worker that has never seen your bar that you must study physics. Show them some facts. Wiki is good for that kind of thing.
Then, What? Once your audience knows a little something. Then, What?
Gee Willikers. You could tease the security people at the local airport. They might take your bar. Don't bother if you are in Canada.

I had a flute in a pcv pipe. It looked like it could be a makeshift bomb. The Americans were on me when I walked into the ticket counter. In Canada no one gave me or my pipe bomb a second look.

How could you go Nerd Sniping with your very heavy bar? There has 'got' to be a way. It would have to be warm, if, you want to 'get' people in physics departments. Who could you 'get'?

Your spouse would be my first guess. But, your spouse has already seen you bar. Both of them. So, you need someone else.

That year that I knew the Chemist, I got 'got' several times. He was fun. Of course, a bunch of it was scary. He would 'get' me with a scary fact. Then, I would 'get' him with a natural wonder. He was running out of scary facts. I still had natural wonders to spare.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

Those that want to Know, Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

Posts: 2403
Joined: Sun Sep 12, 2010 4:44 am UTC

### Re: 0356: "Nerd Sniping"

Ok, this is waaay old, but still, just for those who wish to experiment and dont have a masters education:
the answer for a 49-element grid is 0.774 382 +- 0.000 047. And heres the code:
Spoiler:
Clear[smallRectEq, meshEq, eq, sreqs, meqs, eqsys, potential, \
potentials, solution, currents]

smallRectEq[x_, y_] :=

i[x, y, x + 1, y] + i[x + 1, y, x + 1, y + 1] - i[x, y, x, y + 1] -
i[x, y + 1, x + 1, y + 1] == 0

meshEq[x_, y_, size_, source_] :=

If[x > 1, i[x - 1, y, x, y], 0] + If[y > 1, i[x, y - 1, x, y], 0] -
If[x < size, i[x, y, x + 1, y], 0] -
If[y < size, i[x, y, x, y + 1], 0] + source == 0

eq[x1_, y1_, x2_, y2_] := If[And[x1 < x2, y1 <= y2], Sum[
i[x, y1, x + 1, y1]
, {x, x1, x2 - 1}] + Sum[
i[x2, y, x2, y + 1]
, {y, y1, y2 - 1}] == 1
, 1 == 0]

sreqs[size_, x1_, y1_, x2_, y2_] := Flatten[Table[
smallRectEq[x, y],
{x, 1, size - 1},
{y, 1, size - 1}
], 2]

meqs[size_, x1_, y1_, x2_, y2_] := Flatten[Table[
If[
{x, y} == {x1, y1},
meshEq[x, y, size, i],
If[
{x, y} == {x2, y2},
meshEq[x, y, size, -i],
meshEq[x, y, size, 0]
]
],
{x, 1, size}, {y, 1, size}], 2]

eqsys[size_, x1_, y1_, x2_, y2_] := Flatten[Join[
Table[smallRectEq[x, y], {x, 1, size - 1}, {y, 1, size - 1}],
Table[
If[
{x, y} == {x1, y1},
meshEq[x, y, size, i],
If[
{x, y} == {x2, y2},
meshEq[x, y, size, -i],
meshEq[x, y, size, 0]
]
], {x, 1, size}, {y, 1, size}],
{{eq[x1, y1, x2, y2]}}
], 2]

varsys[size_] := Flatten[Join[
Table[i[x, y, x + 1, y], {x, 1, size - 1}, {y, 1, size}],
Table[i[x, y, x, y + 1], {x, 1, size}, {y, 1, size - 1}],
{{i}}
], 2]

currents[size_, x1_, y1_, x2_, y2_] :=
Solve[eqsys[size, x1, y1, x2, y2], varsys[size]][[1]]
potential[x, y] :=
If[y == 1, If[x == 1, 1, potential[x - 1, 1] - i[x - 1, 1, x, 1]],
potential[x, y - 1] - i[x, y - 1, x, y]]
potentials[size_, x1_, y1_, x2_, y2_] :=
Table[potential[x, y], {x, 1, 5}, {y, 1, 5}] /.
currents[size, x1, y1, x2, y2] // MatrixForm
solution[size_, x1_, y1_, x2_, y2_] :=
N[{1/i /. currents[size, x1, y1, x2, y2],
potentials[size, x1, y1, x2, y2]}]

It uses Kirchoffs equations and some coffee that I drank.
levantis

Posts: 20
Joined: Thu Feb 05, 2009 1:42 pm UTC

### Re: 0356: "Nerd Sniping"

Once I came accross this total moron... that I in retrospect found was in fact brilliant, because he had turned nerd sniping into a money making venture.

What he did was to say something to the effect of "If you cross a street many times, and you havn't gotten hit by a car so far, the risk that you will get hit by a car increases every time you cross". Basicly he said that independent random events were dependent, and not only that: he posted it on a skeptics' forum.

The nerds went berserk and flooded his blog with comments about what an idiot he was; dozens of explanatory examples showing why independent random events do not magically affect eachother; scans of the standard mathametical statistics textbook for swedish universities (he had quoted that one); a simulation program showing empirically that he was wrong (I did that one); post after post after post... upon which he simply replied "No, you're wrong, I'm right" and just kept holding his position like a textbook Dunning-Kruger victim.

I was about to declare him as living proof that you can survive a dual hemispherectomy... but then I noticed the utter brilliance of his scheme: he had get-paid-for-page-views ads on his blog.

It was genius!! His setup was so simple:

1) Get a blog.
2) Put ads on it.
3) Go nerd sniping (or maybe it's more accurate to call it nerd-baiting / nerd-trolling).
4) Profit!!!

Sheer brilliance.

/Michael
MichaelKarnerfors

Posts: 88
Joined: Sun Jan 25, 2009 3:30 am UTC
Location: Sweden

### Re: "Nerd Sniping" Discussion

CNLohr wrote:I was fairly satisfied with my results. So, I plopped in the coordinates for the Knight's move, and ran the test automatically on a variety of number of resistors. A couple results from the middle are as follows:
Spoiler:
4x4 grid (32 resistors): .9955357 ohms
15x15 grid (450 resistors): .7856096 ohms
40x40 grid (3,200 resistors): .7749523 ohms
120x120 grid (28,800 resistors): .7734296 ohms
weighing in at around 514MB memory used, and 66 minutes run time, 320x320 grid (231,200): .7732632 ohms

So, if anyone is interested in a numerical system for solving arbitrary check points and arbitrary sizes for the field of resistors, feel free to check out my code.

http://userpages.umbc.edu/~lohr1/xkcdresistor/

How do you manage to get 32 resistor in a 4 by 4 grid
and 450 resistors in a 15 by 15 grid????

Surely in a 4 by 4 grid you would have 32 resistors???? anyone?
strokebow

Posts: 1
Joined: Tue Oct 11, 2011 10:27 am UTC

### Re: "Nerd Sniping" Discussion

I've made myself a sign.

How did the orbital velocity of the moon effect Apollo 13's lauch?

It's simple (ish) but it works quite well. 10 points so far.
Avenger_7 wrote:You are entitled to your opinion though. Even though it's wrong.

BlackHatSupport

Posts: 38
Joined: Mon Nov 08, 2010 6:34 pm UTC
Location: Wherever you aren't.

### Re: 0356: "Nerd Sniping"

is it meta sniping when they correct you that it should be "affected"?
The time and seasons go on, but all the rhymes and reasons are wrong
I know I'll discover after its all said and done I should've been a nun.

philsov
Not a fan of Diane Kruger

Posts: 1176
Joined: Sat Sep 20, 2008 7:58 pm UTC
Location: Texas

### Re: 0356: "Nerd Sniping"

philsov wrote:is it meta sniping when they correct you that it should be "affected"?

That's half the fun, seeing which ones notice that.
Avenger_7 wrote:You are entitled to your opinion though. Even though it's wrong.

BlackHatSupport

Posts: 38
Joined: Mon Nov 08, 2010 6:34 pm UTC
Location: Wherever you aren't.

### Re: "Nerd Sniping" Discussion

strokebow wrote:
CNLohr wrote:I was fairly satisfied with my results. So, I plopped in the coordinates for the Knight's move, and ran the test automatically on a variety of number of resistors. A couple results from the middle are as follows:
Spoiler:
4x4 grid (32 resistors): .9955357 ohms
15x15 grid (450 resistors): .7856096 ohms
40x40 grid (3,200 resistors): .7749523 ohms
120x120 grid (28,800 resistors): .7734296 ohms
weighing in at around 514MB memory used, and 66 minutes run time, 320x320 grid (231,200): .7732632 ohms

So, if anyone is interested in a numerical system for solving arbitrary check points and arbitrary sizes for the field of resistors, feel free to check out my code.

http://userpages.umbc.edu/~lohr1/xkcdresistor/

How do you manage to get 32 resistor in a 4 by 4 grid
and 450 resistors in a 15 by 15 grid????

Surely in a 4 by 4 grid you would have 32 resistors???? anyone?

Don't ask me how he decided it but his math works out if each unit of the grid can each hold sqrt(2) = 1.414 resistors
Yoduh

Posts: 31
Joined: Tue Sep 20, 2011 3:49 am UTC

### Re: 0356: "Nerd Sniping"

Black Hat Support: I love your signature.
broken_escalator wrote:Everyone knows afros are a hard counter to petrification.
poxic wrote:When we're stuck, flailing, and afraid, that's usually when we're running into the limitations of our old ways of doing things. Something new is being born. Stick around and find out what it is.

UniqueScreenname
A Little Excited

Posts: 1169
Joined: Mon Oct 24, 2011 8:11 pm UTC
Location: The Restaurant at the End of the Universe

### Re: 0356: "Nerd Sniping"

MichaelKarnerfors wrote:Once I came accross this total moron... that I in retrospect found was in fact brilliant, because he had turned nerd sniping into a money making venture.

What he did was to say something to the effect of "If you cross a street many times, and you havn't gotten hit by a car so far, the risk that you will get hit by a car increases every time you cross". Basicly he said that independent random events were dependent, and not only that: he posted it on a skeptics' forum.

The nerds went berserk and flooded his blog with comments about what an idiot he was; dozens of explanatory examples showing why independent random events do not magically affect eachother; scans of the standard mathametical statistics textbook for swedish universities (he had quoted that one); a simulation program showing empirically that he was wrong (I did that one); post after post after post... upon which he simply replied "No, you're wrong, I'm right" and just kept holding his position like a textbook Dunning-Kruger victim.

I was about to declare him as living proof that you can survive a dual hemispherectomy... but then I noticed the utter brilliance of his scheme: he had get-paid-for-page-views ads on his blog.

It was genius!! His setup was so simple:

1) Get a blog.
2) Put ads on it.
3) Go nerd sniping (or maybe it's more accurate to call it nerd-baiting / nerd-trolling).
4) Profit!!!

Sheer brilliance.

/Michael

Now, how to do this without actually having to be a seemingly-stupid person.
webgiant

Posts: 238
Joined: Mon Aug 17, 2009 5:36 pm UTC

### Re: 0356: "Nerd Sniping"

webgiant wrote:
MichaelKarnerfors wrote:Once I came accross this total moron... that I in retrospect found was in fact brilliant, because he had turned nerd sniping into a money making venture.

What he did was to say something to the effect of "If you cross a street many times, and you havn't gotten hit by a car so far, the risk that you will get hit by a car increases every time you cross". Basicly he said that independent random events were dependent, and not only that: he posted it on a skeptics' forum.

The nerds went berserk and flooded his blog with comments about what an idiot he was; dozens of explanatory examples showing why independent random events do not magically affect eachother; scans of the standard mathametical statistics textbook for swedish universities (he had quoted that one); a simulation program showing empirically that he was wrong (I did that one); post after post after post... upon which he simply replied "No, you're wrong, I'm right" and just kept holding his position like a textbook Dunning-Kruger victim.

I was about to declare him as living proof that you can survive a dual hemispherectomy... but then I noticed the utter brilliance of his scheme: he had get-paid-for-page-views ads on his blog.

It was genius!! His setup was so simple:

1) Get a blog.
2) Put ads on it.
3) Go nerd sniping (or maybe it's more accurate to call it nerd-baiting / nerd-trolling).
4) Profit!!!

Sheer brilliance.

/Michael

Now, how to do this without actually having to be a seemingly-stupid person.

Do the opposite? Post legitimate science on a young-Earth creationist site and link to your blog?
forbiddenSpell

Posts: 14
Joined: Sat Oct 29, 2011 4:44 pm UTC

### Re: 0356: "Nerd Sniping"

Just to do a bit more nerd sniping here, what is the solution in a 3d grid!
tomtom2357

Posts: 433
Joined: Tue Jul 27, 2010 8:48 am UTC

### Re: 0356: "Nerd Sniping"

I only just got around to looking up the answers for xkcd 356, and I noticed that by now some of the links have died.

The geocities page is long gone, of course, but is still on archive.org, at http://web.archive.org/web/200602110027 ... node2.html

From that I was able to find an actual current live version of the same article, at http://sites.google.com/site/resistorgrid/

A better source however (because it has a table giving solutions for many different choices of which two nodes are "marked red" in the problem statement) is the paper by Atkinson and van Steenwijk. A link was given to http://atkinson.fmns.rug.nl/public_html/resist.pdf, which has also gone missing. But Google Scholar turns it up at http://pds4.egloos.com/pds/200708/06/25 ... ariski.pdf

There is a fine line between sniping and trolling. It might have been fun to point out that
\sqrt{\pi}-1=0.772453...

which is only a bit less than
\frac{4}{\pi}-\frac{1}{2}=0.773239...

and ask why it can (or cannot) be one or the other.
Robert Munafo - http://mrob.com - @mrob_27
Adblocking Animated Avatars, Always.

mrob27

Posts: 16
Joined: Tue Jun 28, 2011 2:19 am UTC
Location: Cambridge, USA

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