NMCLL is the name given to the last layer of corners when one layer is offset by 90 or 180 degrees. It is a subset of A2 and can be used as a 2x2 method in combination with, and using the same algorithms as, CLL. NMCLL is also used in 3x3 methods, such as Roux, ZZ, and Petrus when matching or non-matching blocks are built. NMCLL was originally proposed by Gilles Roux for the Roux method and the recognition method of using the L/R color orientation along with pre-determined pattern positions was co-developed by Gilles Roux and James Straughan.
During a solve, it isn't initially required that the bottom layer of corners match. In Roux, for example, this gives four options for the second block. These pseudo blocks also have an effect on the U-layer corners. More stickers from the F, B, and D layers can be mixed in. While any recognition can be used, the traditional ways are difficult to use with all non-matching corner types. A recognition method has been developed specifically to solve this problem and works equally well with matching and non-matching corners. All of the same algorithms are used, though memorization of two patterns per algorithm is required. The use of this technique reduces the number of moves in the solve. This is useful for any method that has a corner solving step, such as Roux, ZZ+COLL, and CLL/EG.
Step 1: Within the U layer corners, find the orientation of the colors that are on the left and right side of the cube. If your cube has yellow on the top and blue on the front, that means you will look for the orientation of the orange and red colors.
Step 2: Check the pre-determined positions for matching colors.
This has the same recognition speed as the method used by speedsolvers for normal corners. This method works equally well for both matching and non-matching corners. Just like usual recognition methods, users can change the pre-determined pattern locations to better fit their own style or to perform recognition from all angles.
The below image shows the possible orientations and the places to look for matching colors. The blue lines show the two sets of matching stickers. A case will have both sets of matching stickers, one set, or no set at all.
The below image shows each of the 42 CLL cases. Each CLL case has two possible orientations. The L/R orientations are listed along with their individual patterns. Orange and red are the L/R colors and the white colors are the locations of matching colors as described in the Orientation section above. The lines show the positions of matching colors. A pattern can have 2, 1, or 0 sets of matching colors. A complete algorithm list for the NMCMLL version can be found at the bottom of this page.
Below is a chart for those transitioning from a different recognition method. This chart shows the patterns for both recognition methods so that they can easily be compared.