Hey guys, I'm new here and Melinda suggested I check out the group and post=
about Spinpossible and some of the open math surrounding it.
Spinpossible is a (free) puzzle game that you can play here: https://spinpo=
ssible.com/index.pl or on your iphone or android phone.=20=20
The idea is very simple. There are 9 tiles, ordered 1-9 and laid out in a =
grid. You can manipulate them by rotating any rectangular group of them 18=
0 degrees. The goal is to get all tiles right-side up, in order, 1 through=
9.
Despite the simplicity, the game is extremely challenging and there are a l=
ot of deep group theory questions related to the game, for more details see=
this paper on archiv, http://arxiv.org/abs/1110.6645. Some of the simpler=
interesting results are that,=20
(a) every puzzle can be solved in at most 9 spins.
(b) every puzzle can be solved in at most 9 spins even if you are not all=
owed to spin individual tiles
However, all these results have been shown only by brute force, computation=
ally and the 4x4 version of the game, with 16 tiles, is believed to be comp=
utationally intractable.
Researchers both in CS and in Mathematics worldwide have gotten interested =
in the game and we had a very successful presentation at the JMM 2012 in Bo=
ston where a math professor recommended I get in touch with Melinda Green a=
nd post to this group, so I hope you enjoy it.
We're still tweaking the puzzle so any helpful suggestions/comments are gre=
atly appreciated.
Thanks!
Alex Sutherland