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Hey everyone, I just thought I'd ask a question with some cerbral weight. I've been solving rubik's cubes for a couple of months now and was wondering if anyone else has been able to work out the math and logic needed to solve these puzzles.

I haven;t done a cube for too many years than I care to remember but back in the days when it first came out I could solve a mixed up cube in around 90 to 120 seconds.

I never could work out the math but there was a system that was easily memorised and I'm sure that thousands knew of it and could do the same.

Once you knew the system it was just a matter of how quickly you could put it into practice.

monker59 wrote:Hey everyone, I just thought I'd ask a question with some cerbral weight. I've been solving rubik's cubes for a couple of months now and was wondering if anyone else has been able to work out the math and logic needed to solve these puzzles.

There are competitions in solving the cube on time and its quite amazing, but the top elite solves it virtually always below 15 sek. An average solving time of 30s is considered achievable with a few mouths practice and very good memory. To solve it fast you need to have memorized solutions for most configurations on the bottom layer. On line are many resources for rubik's cube.

I solved the cube many years ago when I was in high school. If you think of different sequences of actions on the cube as elements in what mathematicians call a group, I noticed (and most people who solve it from scratch notice something similar) that group elements of the form ghg* where gg*=1 often leads to useful operations. In more plain terms it is often good to consider a sequence g of actions, followed by an action h, followed by the inverse sequence g* of g. The reason is that g followed by g* brings you back to scratch, so when you insert h in between sometimes this brings you "partly" get back to scratch with maybe only a few mini cubes in different positions.

As it happens most useful sequences are of the form ghg*
I think some of the sequences used by top rubik's solvers have been
found by computer. To get a decent time you need to take the cube apart and tune it by for example applying potato powder.

I learned how to solve the cube a few weeks ago. It's really not that difficult; like dat said, once you've memorised the moves (which is the hardest part) it's just a matter of doing it as quickly as possible. I'm quite slow (1min 45sec on average) compared to all those speed cubists out there, but I'm just pleased I can do it! I should add I didn't work it out myself. After days of trying to do just that, I cheated and looked up the solution. Mind you, even when you know the solution, you still have to put the mental work in to memorise all those moves and know when to apply them.

I got myself a Rubik's Revenge cube (4x4x4) from Amazon the other day. It is my next challenge.

To answer your question, no, I have no clue.

And as an interesting aside, I have found that I get very good reactions just from solving the cube for people. I sometimes think they prefer it to my magic - they certainly appear to be quite impressed by it!

52 second for me. Using the non-speed method, which I intend to learn soon!

its also rhyming slang round my parts

Rubik´s Cubes are the new "black". The maths you say? You can get the "route" guide online and it´d tell you the moves necessary at which point. It´s a very clever (and cool - I maintain that despite what the others say!) bit of kit. Of course don´t do it in bar...

This might be of interest:

http://en.wikipedia.org/wiki/Rubik's_Cube

Replicant wrote:I got myself a Rubik's Revenge cube (4x4x4) from Amazon the other day. It is my next challenge.

Hey, if you need some help, let me know. I've got it down pat.

Will do! And don't call me Pat.

(Now, where's my coat...?)

Around your parts??

Understand what you mean but ......

There's two main ways to solve a rubik's cube for speed. One way involves making a cross on the first face and then continuing to complete the first layer, followed by the second layer, etc. This method, I believe, is covered in the solution book that is published by the rubik's company. The second method - and the one I use - involves working from a corner and spreading outward. Here's a really good website that covers this second method: http://lar5.com/cube/

I'm not incredibly fast at solving cubes, but my record time is just under 40 seconds (which I've never been able to come even close to a second time...) I enjoyed learning how to solve one though and it definitely does entertain a small group of friends...the first time or two...