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Interesting Little Puzzle

Posted on 21 May 2007 by


I don’t know about any of you, but I love puzzles. Here is a quick little puzzle I found via Vicott over at Mobile-SG. The object is to hook up the three utilities to the three houses, without crossing the lines (uhm, at least don’t cross the beams until the Stay Puff Marshmallow Man attacks the city.)

supuzzle.jpg 

It sounds simple. When I saw it, I figured I would have it solved in a matter of minutes. Sorry to say, I am on day 2 and just as puzzled as I was when I started. Vicott claims to have solved the puzzle, and I am anxiously awaiting his promised solution. If you are able to solve it, feel free to post your solution here.

http://www.supuzzle.com/

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  • reidme

    If it’s the same puzzle I remember from when I was a child, the solution is for one of the lines to go “under” one of the houses. That way it doesn’t “cross” any other lines.

  • reidme

    Well that’s not it. I just tried it and it wouldn’t let me do that.

  • http://www.justanothermobilemonday.com Doug Goldring

    Yeah, Reidme. I was figuring it had something to do with concentric circles, but I haven’t gotten it yet. :)

    Doug

  • reidme

    Apparently it’s impossible without the trick I mentioned. :-(

    http://mathforum.org/dr.math/faq/faq.3utilities.html

    http://www.afunzone.com/utilitiespuzzle.html

    Mark

  • reidme

    Apparently it’s impossible without the trick I mentioned. :-(

    http://mathforum.org/dr.math/faq/faq.3utilities.html

    Mark

  • http://www.geardiary.com Allen Hong

    :P I just tried it a few times. Yep, look impossible.

  • http://www.geardiary.com Mitchell Oke

    I’m pretty sure it is impossible. It is easy to get 8 lines without crossing, but the 9th line ALWAYS has to cross something.

  • http://www.justanothermobilemonday.com Doug Goldring

    Yup. That is where I am stuck as well. I can get 8 lines every time. :) Vicott swears he has solved it. So, we’ll see what he comes back with. It would be patently unfair if the solution involves the theory suggested by reidme, because my computer screen does not fold like that. :)

    Doug

  • http://www.geardiary.com Mitchell Oke

    Did a bit of googling, and it would seem to be a mathematical fact that it is unsolvable unless you cheat with a piece of paper and draw a line on the back :P

  • http://www.justanothermobilemonday.com Doug Goldring

    Yeah, that was the solution suggested by reidme in his link above. I don’t really find that to be an adequate solution. If you are going to present a puzzle, it must be solvable in the format you present it. I can’t flip over my laptop, punch a hole in the screen and roll it up into a tube. Oh well.

    Doug

  • reidme

    it’s definitely a dirty trick. Sorry about the double post, it didn’t seem to post the first time.

  • http://www.geardiary.com Judie Lipsett Hughes

    “If you are going to present a puzzle, it must be solvable in the format you present it.”

    Maybe there is some back-door trick we are all missing? Either way, it drove me nuts for a while. Thanks Doug! ;-)

  • http://www.justanothermobilemonday.com Doug Goldring

    Yeah, it definately hellped me waste an hour or so yesterday. I’m a big fan of puzzles, but not unsolvable or dirty trick puzzles. Hopefully, when we see the solution there will be some aha catch to the whole thing (is it possible to string the utilities through the houses).

    Doug

  • reidme

    I tried going through a house, but as soon as you touch the house it stops.

  • http://www.pocketpcthoughts.com Janak Parekh

    This is a classic Computer Science problem. The theoretical answer is that it is impossible from a purely theoretical standpoint.

    http://en.wikipedia.org/wiki/Planar_graph

    The “graph” that you’re trying to draw is a K3,3, i.e., a bipartite graph where you have two groups of nodes, and each node from each group connected to every node of the other group. It has been formally proven that this cannot be done in a 2D plane.

    So, if there is a “solution”, it involves a trick that’s specific to the puzzle or its UI (like, as someone mentioned, stringing through a house). I haven’t played with it, but if you continue to do so, make sure to look along those lines.

  • reidme

    What he said. ^

  • http://www.justanothermobilemonday.com Doug Goldring

    Well, at least I feel less stupid now for not being able to figure it out. Still, what is the point of an unsolvable puzzle except to frustrate people like me. Typically, when you see a puzzle like this, there is always a solution, even if it is sometimes extremely difficult to find. Maybe later I will find a solution with no puzzle and we can match them up.

    Doug

  • http://www.pocketpcthoughts.com Janak Parekh

    “Still, what is the point of an unsolvable puzzle except to frustrate people like me.”

    I’m guessing it’s either a prank, or a test to think outside the box. :(

  • perryman

    Yeah, I think it’s a bit of a dirty trick to post a puzzle with no possible solution! I just wasted a fair amount of time trying it.

  • http://www.ilcicali.com sardauker

    Doesn’t electricity gets the houses by poles in USA too?

  • http://www.pocketpcthoughts.com Janak Parekh

    “Doesn’t electricity gets the houses by poles in USA too?”

    Yes, most electrical wiring in the US is indeed overhead. Some city downtowns (esp. places like New York) have underground wiring. But, remember, wires *can* cross in real life — we’ve got a Z dimension. ;)

  • http://www.justanothermobilemonday.com Doug Goldring

    Well, I am very disappointed. Vicott posted his solution over at MObile-SG:
    http://mobile-sg.com/simpleblog/archives/post.asp?id=1135

    It seems he had not solved it after all. Notice the left house is not connected to the green electricity. :( Looks like this really is unsolvable as you guys mentioned.

    Sorry, I am just as frustrated by this one as all of you.

    Doug

  • tabi13

    Janak Parekh is ABSOLUTELY 100% correct that a solution requires it being a K 3,3 bipartite complete graph which is mathematically proven to be imposible in a 2D plane. Unless there is a hidden eggdrop in the flash game, there is no solution!

    Discrete Mathematics 101 :p

  • http://www.pocketpcthoughts.com Janak Parekh

    “Discrete Mathematics 101 :p”

    Yeah, I taught the course one summer when I was a Ph.D. student. ;-)

  • http://www.geardiary.com Mitchell Oke

    Lol, his “solution” is the same point that everyone got up to, but everyone else realized it isn’t finished yet :P

  • http://www.justanothermobilemonday.com Doug Goldring

    Discrete Mathematics 101…that was not part of my English curriculum. :)

    Doug

  • http://www.geardiary.com Mitchell Oke

    Hey it looks like he has made the two electricity lines unnecessarily long just to make it look finished. You could easily just draw a 3cm line directly from each house :P

  • http://www.geardiary.com Judie Lipsett Hughes

    “Discrete Mathematics 101…”
    Nor was it one of my Animal Science courses, either. ;-)

    Thanks Janak. :-)

  • reidme

    “Discrete Mathematics 101…”

    I guess that’s math you don’t talk about.

  • http://www.pocketpcthoughts.com Janak Parekh

    “I guess that’s math you don’t talk about.”

    Cute. ;-) Fortunately, it’s Discrete Math, not Discreet Math…

  • Sewii

    There is a solution, not a fair one but I got it. There is a solution because you’re using flash to solve it. Draw the 8 lines, but for the last one you have to go through one of the supplies. Draw the last line going under one of the supplies, but before touching the supply do a right click and select forward. Now the line went though the supply and you can finish it. Have anice day fellas.