# Request sequence of basic operations to solve edge and corner



## Zhiguo (Mar 8, 2010)

Recently I am writing a program to solve 20x20x20 cubes. Since I am not good at solving cubes myself, I posted messages on this forum and many good guys replied and helped. One of this good guys give me two formula:

(1) For center: xR U' yR U xR' U' yR' U
(2) For edge/corner: r U2 r U2 F2 r F2 l' U2 l U2 r2

The first formual is very very powerful. With this single formula(with all kinds of iterations of course), the program now can solve all the central area of a randomly-messed-up 20x20x20 cube. Now, it is time to solve the edges and corners. But I do not quite understand the second formula. Could anyone explain a little more about it?

Generally speaking, I need a sequence of basic operations to change the edge/corner piece. The central area which is already ok should remain ok. And this sequence of operations should make as little change as possible(for example, ex-change two pieces?).

Thanks again! Any help will be appreciated!


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## Lucas Garron (Mar 8, 2010)

Zhiguo said:


> But I do not quite understand the second formula. Could anyone explain a little more about it?


r U2 r U2 F2 r F2 l' U2 l U2 r2


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## Zhiguo (Mar 11, 2010)

I have finished the program. Thanks!


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