homework from university. (Flips)

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homework from university. (Flips)

Postby patatafrita » Thu Aug 08, 2013 11:47 am

Hey you,

first of all, my english is not pretty good and I am not here to get to know how to solve the cube.
I got an excercise at university and I'm desperate.

I've to do this:

first step: two neighbouring edges of the up-layer need to be flippedb (every other cubie is in the right position)
secondly: after that I need a new algorithm to flip two opposite edges of the up-layer (every other cubie is in the right position)
the last step: I have to do the first algortihm backwards in order to flip two neighbouring edges of the up-layer again (every other cubie is in the right position=

the second algorithm my prof gave me is like that:
U- F R- U F- R L- U B- R U- B R- L

I have a solution, but this one is not allowed

1. R L F R2 F R- L D- R2 D2 F2 L2 B2 U- R2 B2
2. L2- B2- U L2- F2- R2- D2- B2- D F- B R- B2- R- F- B-
3. B2- R2- U B2- L2- F2- D2- R2- D L- R F- R2- F- L- R- (the first one backwards )


as you can see the second step does not agree with the algorithm my prof' mentioned.

I really hope to have someone who can give some advice.
I would be thankful.
patatafrita
 
Posts: 3
Joined: Thu Aug 08, 2013 11:25 am

Re: homework from university. (Flips)

Postby Sharkretriver » Thu Aug 08, 2013 5:38 pm

Your solution works (tried it on a cube) but is not allowed? Maybe you should post the rules that your prof gave here so the algs and tips we pass are relevant, because your algs do the steps properly.
lol, here to help ^_~
Sharkretriver
 
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Location: Toronto, Canada

Re: homework from university. (Flips)

Postby patatafrita » Thu Aug 08, 2013 5:45 pm

yes, my solutions works and it annoys me I'm not allowed to use it.

I have to use this algorithm for the second step.
U- F R- U F- R L- U B- R U- B R- L
This is the only requirement
patatafrita
 
Posts: 3
Joined: Thu Aug 08, 2013 11:25 am

Re: homework from university. (Flips)

Postby Sharkretriver » Fri Aug 09, 2013 12:08 pm

The only way that alg can be used is as follows:
After your first alg, you have
000
00x
0x0
Where x is a flipped edge.
You need
000
x0x
000

and that is impossible using the second alg because adj can't directly go into opposite without adj alg/alg #1...UNLESS
you use setup moves so that when you execute the second alg and undo the setup moves (conjugate) you get the opposite edges.
I won't say the setup moves because it's not difficult. (2 moves)
After, you can just use your third alg.
lol, here to help ^_~
Sharkretriver
 
Posts: 367
Joined: Thu Jul 14, 2011 10:11 pm
Location: Toronto, Canada

Re: homework from university. (Flips)

Postby patatafrita » Fri Aug 09, 2013 3:36 pm

I'm about to give up :P

or is there another possibility at all?
I mean, is there any other formation possible in the first step?

My excercise demands for one algorithm and the undo of it. The main thing is, that in the second step two opposite edges are flipped and in the last step two neighboured ones. Maybe the edges don't need to be flipped after doing the first alg.
patatafrita
 
Posts: 3
Joined: Thu Aug 08, 2013 11:25 am


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