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Tim Harford: What Prison Camps Can Teach You About Economy

ChaosEngine says...

Geometry and economics are not in any way comparable.

Geometry worked before humans evolved and will continue to work long after we're going. It has no need of human input.

Economics, on the other hand, is entirely dependent on human behaviours. Rationality might be a factor, but you would have to be willfully ignorant of history to argue that human behaviour is always rational.

Economics is not a science, and it's certainly not logical.

Honestly, you could not have picked a worse comparison. Imagine if Pythagoras' Theorem was "the square of the hypotenuse is mostly, kinda equal to the sum of the squares of the other two sides"? Or "the sum of the angles in a triangle is 180 (except on rainy days)"?

Trancecoach said:

Economics is not a matter of faith. It's a matter of rationality. Logic. The laws of geometry do not change on the basis of one's interpretation. Same is true in economics.

Duke Engineering's new four stroke "axial" engine

newtboy says...

A rotary (Wankel) engine has a triangular device that acts as the piston, which rotates in a chamber close to a figure 8 shape. Each side of the triangle acts as it's own piston as it rotates, first intake through a port (no valve) then compression, detonation, expansion, and finally exhaust through another port (still no valve).
Radial engines (what I think you meant) are relatively normal piston driven engines where the pistons are arranged in a circle around the crank at a 90 deg angle from the cranks rotation. These are usually used in prop driven airplanes.
This motor arranges the pistons in the same orientation as the cranks rotation...a 90 deg difference from radial engines. This makes it far more compact, but also puts the pistons in a single, rotating, revolver like arrangement of cylinders. It's a bit of a combination of rotary and radial engine features.

artician said:

How is this different, or more efficient, than a Rotary Engine:
http://en.wikipedia.org/wiki/Rotary_engine

(Videosift should add support for HTML links... wait, what?) @dagg

Snooker - Ronnie O'Sullivan final frame in Welsh Open Final

aaronfr says...

In theory, the player performing the break could pot a red and then continue on that break, but that would be extremely unlikely and probably a very bad move. At no point in snooker do you get two shots in one turn, not even on the break.

The break shot requires that the player hits a red ball first. Since the pink is at the top of the rack (the triangle of balls), this prevents the player from breaking like you would in a game of 8 or 9-ball. Therefore, you are unlikely to get a red ball to move with enough momentum to make it to a pocket. And if you did manage to do that, everything on the table would be scrambled to hell which does not lend itself to easy, predictable shots or high scores (following the red-black-red-black pattern).

So, instead, in snooker the perfect break sees the cue ball striking one of the bottom corner balls, sending it in to the bottom cushion with the momentum moving along the back line of balls sending the other corner ball into the side cushion. Ideally, both of those balls will return very close to their starting position with the rack essentially undisturbed. At the same time, you want the cue ball to move around the table and come to rest either against the top cushion (as far away from the reds as possible) or hidden behind the green, brown, or yellow ball.

TLDR: No, breaks in snooker are defensive in nature.

iaui said:

Thanks for the rules explanation. I have one more small question: What are the rules of the break? Does the initial break shot have to put a ball down in order for the breaker to continue play or does the breaker get a break shot and then a next shot no matter whether a ball is sunk or not?

The Mast Walk - Diving To The Ocean

BicycleRepairMan says...

I make it 36 degrees from 0:35 in the video, considering the mast is 30 meters from the deck, lets make the hypothenus 32 meters from the base of the triangle (ocean surface), that makes the jump 18.81 meters
sin(36)*32 meters= 18.8091280734
Depending on how the 30 meters are measured, and accounting for the difference in angles in video/reality I'd say the dive is between 17 and 20 meters.

Why 'Pulp Fiction' Is Really a Modern Remake of King Arthur

ChaosEngine says...

Pretty tenuous links there.

So Wallace, Vincent and Mia are Arthur, Lancelot and Guinevere ....

OR....

pretty much any love triangle in the history of fiction?

Briefcase=holy grail is probably the best bit, but Butch as Mordred doesn't work at all and neither does Jules as Galahad. Butch is not Wallaces son (where's Morgana?) and Jules is actually older than Vincent. Also, Morderd didn't kill Lancelot, and Mordred killed Arthur, he didn't save him from rape.

Animal Odd Couples

Orz says...

I think it is arrogant and selfish for us to commonly refer to these examples as "human behavior". Twice on the same stretch of country road I stumbled upon a most unlikely group that consisted of a sparrow, a rabbit and a squirrel standing together in a triangle. One can only assume that they were conversing or relating to each other in some way.

Magic: Peter Marvey - Le velo

RFlagg says...

You see that guy walk away at 2:08 and back again about 3:27. I'd guess he is there to help assist the magician fold and unfold his legs into his white suit so that his legs become his chest while he pushes his butt back into that triangle behind him. The girls of course distract you from that guy and the magician's odd squirming... Still, live for the first time it is probably a neat trick.

bobknight33 said:

There is a guy walking up behind the act and getting to the box.
Most are too busy looking at the smoking girls to notice.
When the girl walks behind with the unicycle she goes around back and comes around empty handed and during that time you can see " other" feet walking behind the box

The other "feet" show up again after the magician gets back together and the door closed to put himself back together

enoch (Member Profile)

Super-Fast Flight of the Bumblebee

Little Russian Girl is a Car Expert

Kid not sure how to handle broken cymbals during anthem

zor says...

Great save! Unfortunately, he was demoted to the triangle and if he screws that up they'll put him on the rain stick or sandpaper blocks.

How does he do it?

poolcleaner says...

We did this puzzle in elementary school in the GATE program. How on earth people aren't taught, amazed, and remembering this simple but awesome geometrical illusion is beyond me. First thing you see when you try to recreate it on a grid, is that there is missing diagonal space. People miss the missing space isn't using the same modular shape as the rest of the puzzle. Easy to detect on a grid using only a triangle.

How does he do it?

Stormsinger says...

You've clearly got the right explanation, but now I wonder just why he had the video cut in those two places. All it did was add yet another opportunity to cheat (which is all that the near-triangle gimmick is, really).

xxovercastxx said:

@Stormsinger: I've seen this done in real life and there's no such trickery needed. This puzzle was presented in another sift (which I can't find) a few years ago along with a link to a downloadable PDF that you could print and cut out the shapes.

edit: It works similarly to this: http://en.wikipedia.org/wiki/Missing_square_puzzle

edit2: The other video I was talking about is http://videosift.com/video/Illusion-The-Impossible-Puzzle

The problem in Good Will Hunting - Numberphile

TheFreak says...

lol I wasn't paying attention in a discrete math class one day and at the end there was a problem on the board for extra credit. Given a position in a series, find the number. I thought about it for about a week until I made the connection to Pascal's triangle. Wrote an equation 30 minutes before class, because it had been due the class before and as long as I got it in before the next class started it wasn't late. Just for good measure I inverted it and solved for the positon in the series given a number. Then I wrote a dumb, long rambling description of my thought process in deducing the answer. Rushed it to the professor's office and handed it to him just as he was getting ready to leave for class. I sat watching him silently reading it over until I felt compelled to apologize for the incoherent preface. He didn't answer and I excused myself and went to class feeling kind of dumb.

The professor showed up about 20 minutes late for class and explained how the assignment had been to create a simple formula to "aproximate" the position, something like, the number will be no higher than (x-1/y)(y/x-1) or some other nonsense. He hadn't ever seen an actual precise solution until that day.

Score 1 for not paying attention in class.

Why You Should NEVER Pump Iron Alone.



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