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Skip The Water

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Re: Skip The Water

#11

Post by anigbrowl »

patio11 wrote: post #5

In a similar vein: There was a Japanese TV program a few years ago testing talented youngsters. One brain teaser was "On this table you have six match sticks of equal length. Arrange them such that you create four triangles." The match sticks are presented lying flat on a table, and approximately everyone tries to solve the problem in 2D and fails hideously. The right answer, which is a peculiar kind of perverse clev…

There's a better way than a star of David, that gets you exactly 4 triangles in 2d using 6 matchsticks.

Re: Skip The Water

#12

Post by shard »

anigbrowl wrote: post #11
patio11 wrote: post #5

In a similar vein: There was a Japanese TV program a few years ago testing talented youngsters. One brain teaser was "On this table you have six match sticks of equal length. Arrange them such that you create four triangles." The match sticks are presented lying flat on a table, and approximately everyone tries to solve the problem in 2D and fails hideously. The right answer, which is a peculiar kind of perverse clev…

There's a better way than a star of David, that gets you exactly 4 triangles in 2d using 6 matchsticks.

Do you mean a box with an x through it? I guess the rules never said the ends of the matchsticks had to match up either. I'm definitely enjoying all these different answers which explore (exploit?) the imprecisely specified problem.

Re: Skip The Water

#13

Post by narag »

This similar story is also related to programming. The B-Tree is a "skip the water" idea. Instead of using complex algorithms to balance the tree, it's the tree itself that autobalances, splitting nodes when they're crowded or joining them when they're too empty. That's one of my favourite ideas in programming.

Re: Skip The Water

#14

Post by drblast »

I love these competitions, and have been captivated by them since I was a kid after seeing a PBS special on MIT's Woody Flowers, who organized them.

And in high school, I designed a project for a state-wide King of the Hill type contest by ignoring the "goal" and focusing on the tie-breaking rules.

The idea was to design a car (using a strict list of household items) to run up a two-sided hill and rotate a long, hanging metal bar against a sensor multiple times. Your opponent also had a bar on the opposite side of the hill. You'd get a point for each time the bar hit the sensor.

Most people spent a significant amount trying to figure out how to rotate the bar. Most points won, after all.

Except that, if nobody scored, the tie breaker was distance; if you made it up the hill further or even made it to the opponent's side of the hill, and nobody "scored", you'd win.

My "car" used the maximum allowed number of mouse traps in an attempt to sling itself over the hill as fast as possible and flip the other car or device over, or at least disrupt the opponent's operation enough so that nobody would score, and I'd win on distance.

Turns out that the scoring objective was so difficult that this was the winning strategy. Still have the car and the t-shirt, but not the $1000 savings bond. And as popular as sports are in the U.S., I did make more competing in nerd competitions than I did on the track team. :-)

Re: Skip The Water

#15

Post by [deleted] »

patio11 wrote: post #5

In a similar vein: There was a Japanese TV program a few years ago testing talented youngsters. One brain teaser was "On this table you have six match sticks of equal length. Arrange them such that you create four triangles." The match sticks are presented lying flat on a table, and approximately everyone tries to solve the problem in 2D and fails hideously. The right answer, which is a peculiar kind of perverse clev…

[deleted]

Re: Skip The Water

#16

Post by zck »

shard wrote: post #12
anigbrowl wrote: post #11

Earlier quoted context omitted.

There's a better way than a star of David, that gets you exactly 4 triangles in 2d using 6 matchsticks.

Do you mean a box with an x through it? I guess the rules never said the ends of the matchsticks had to match up either. I'm definitely enjoying all these different answers which explore (exploit?) the imprecisely specified problem.

That's still more than four triangles -- two right triangles next to each other that way make a larger triangle. One way to make only four triangles is:

	  \  	   /	
	   \   	  /    	
     -------\----/------
       	     \1	/ 	    
       	      \/  	    
       	      /\	    
     \ 	     / 	\      	 /  
      \	    / 2	 \    	/  
    ---\---/------\----/-  
       	\3/    	   \4 /	  
       	 \     	    \/ 	 
	/ \	    /\ 	
       /   \	   /  \

Re: Skip The Water

#18

Post by Wilduck »

An example that is applicable to real life:

In trying to find jobs, most people dive right into the water of resumes and applications. You may be somewhat successfull with this approach (like the author making it past the first round), but there's a clear advantage to skipping the water. Find someone who can give you the job you want, and convince them to give it to you.

Personally, I've never gotten a job through applications, and have gotten many great jobs simply by emailing people. Or, I suppose, you could start your own business.

Re: Skip The Water

#19

Post by 3pt14159 »

Reminds me of our bridge making challenge:

Given a set of Popsicle sticks, glue and metal wire we were to build a bridge that spanned 3 feet. The winner was the one that could design the bridge such that the force (uniformly applied in the middle third of the bridge) divided by the squared weight of materials used was the winner.

I had the bright idea to totally minimize wood usage, wrap every single joint in wire then cover it with five layers of glue, and prestress the entire bridge to get the most out of the wire.

Our bridge was so ugly that when we put it down the prof and all the viewers from class just started laughing. We ended up winning (just barely though, someone else had a similar type of hack that I can't remember). Of course we didn't hold that much weight (33 percentile), but ours was by far the lightest.

Re: Skip The Water

#20

Post by noahlt »

A tangentially related story:

Talented secondary school kids all across America end up doing egg drop competitions all the time. But the rules of each competition are each slightly different. A friend of mine was in a competition which was scored like this:

Score = (intactness of egg, as 1 or 0)/(distance to target)/(mass of egg-protecting device)

While everybody else designed careful egg encasements, but my friend played video games and read sci-fi novels. When it was his turn to test his "device", he grabbed the egg and threw it away from the target, into a nearby bush, which broke the fall and kept the egg intact.

His great distance from the target would have made his score very low. But since he didn't actually have a device, the judges were forced to divide by zero...

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