

Planarity - a game with planar graphs - infinity
http://www.planarity.net/

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jurjenhaitsma
This is pretty choice - reminds me of untangling a circuit layout... Never
really looked into it that much, but I'd imagine there must be a mathematical
technique that can be applied. My first instinct has always been to put the
point with the most connections in the centre, then map out from that.

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eru
Good luck. The problem may be NP complete in general.

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shrughes
Well, for the cases on planarity.net, it seems O(n) to me. Or maybe something
like O(n log n)

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gjm11
It's O(n) in the general case, so certainly also for the special cases on
planarity.net.

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eru
Could you give me a source or the name of the algorithm, that allows this
running time?

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gjm11
The Wikipedia article on planarity testing cites, for instance, this paper:
<http://jgaa.info/accepted/2004/BoyerMyrvold2004.8.3.pdf> which describes a
not-insanely-complicated algorithm that constructs planar embeddings (or
proves they don't exist) in linear time.

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madair
It would be interesting to couple this game with user profiles that include
questions related to mysteries and observations in cognitive science. Thinks
like left/right handed, formal education, would be interesting too.

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barrettcolin
Spooky: there is an almost identical iPhone game called 'The Plateau'. Screens
here: <http://www.tuaw.com/photos/the-plateau/1270610/>

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smanek
I remember playing playing Planarity well before the iPhone came out, so 'The
Plateau' is just a copy.

In fact, the "Way Back Machine" shows Planarity, basically unchanged, in 2005:
[http://web.archive.org/web/20050731231914/http://www.planari...](http://web.archive.org/web/20050731231914/http://www.planarity.net/)

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derwiki
I think this game won John "One of the Most Interesting People In Cleveland"
when he wrote this sophomore year at CWRU. I'm happy to see that his project
is still being enjoyed!

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gord
Highly addictive... Got to 1500 odd, had a sneak peak at level 30 then
gracefully bowed out.

Used a combination of heuristics - move a vertex to the centroid of its
neighbors, and move randomly to reduce edge intersections.

eyes burning.

