Difference between revisions of "2-Sided PLL Recognition"

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* [http://www.speedsolving.com/forum/showthread.php?41108-Two-sided-PLL-recognition-guide mark4952]
 
* [http://www.speedsolving.com/forum/showthread.php?41108-Two-sided-PLL-recognition-guide mark4952]
 
** [http://www.speedsolving.com/forum/attachment.php?attachmentid=2753&d=1364326050 Direct PDF link].
 
** [http://www.speedsolving.com/forum/attachment.php?attachmentid=2753&d=1364326050 Direct PDF link].
 +
** [http://www.speedsolving.com/forum/showthread.php?47674-New-2-Sided-PLL-Recognition-Guide&p=979385#post979385 paritycase]
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** [https://www.dropbox.com/s/r1j01hd5lhamjjt/PLL%202-Sided%20Recognition%20[V1.0]%20by%20Parity%20Case%20.pdf Direct link to PDF in Dropbox].
 
* [https://www.youtube.com/watch?v=4bNblQQ_P-o crazybadcuber] (video)
 
* [https://www.youtube.com/watch?v=4bNblQQ_P-o crazybadcuber] (video)
 
* [https://www.youtube.com/watch?v=ptJ09-4mciI Joseph Skyler] (video)
 
* [https://www.youtube.com/watch?v=ptJ09-4mciI Joseph Skyler] (video)

Revision as of 07:59, 19 May 2014

2-Sided PLL Recognition (sometimes called "1-Look PLL") is the task of recognizing a PLL from only two adjacent sides (e.g. F and R). This allows a cuber to determine what moves to do as soon as (s)he reaches PLL, without extra AUF turns or cube rotations.

Why 2-Sided PLL Recognition is Possible

2-Sided PLL Recognition is possible because:

  • There are three visible corners, which are uniquely determined. This also determines the hidden one.
  • There are two visible edges.
  • The two hidden edges could be swapped in two different ways. However, given all the visible information there is only one possible way for a valid PLL. This is due to parity.

Therefore, it is possible to tell exactly where each LL piece is (and which PLL case it is). Unfortunately, this is only "barely possible". Unlike OLL (viewed from 3 sides), very few stickers are redundant. For 2-sided PLL recognition, t is sometimes necessary to look at 5 (out of 6) stickers carefully, because changing any one of them could create another valid case.

Existing Systems

Also search for "2-Sided PLL Recognition" for more speedsolving.com threads.