Some have changed the shape completely from a cube to a cuboid (and various other shapes), some have only seen simple sticker modifications. Opposite centres – Solve the centres of two opposite faces by matching up all of the centre pieces of that colour. Note: The r2 notation refers to the Inner-R layer ONLY (an R move would be the outer R layer, and a Rw would be both the outer and inner layers). There are 21 defined PLL cases – These are cases that can appear on a 3x3 cube, there are no more combinations of pieces.

Orient: On official WCA competitions cube puzzles and Megaminx are scrambled with the white face on top and the green face on the front. Last two centres – Use commutators and puzzle knowledge to solve one of the last two centres, leaving the last centre solved. The first centre can be made by connecting two pieces together (in fact, most of the time there will already be one of these 1x2 “bars” solved on your cube due to the limited amount of possible centre combinations).For more examples or to see this in action please set the scramble length to 1 for a 11x11x11 cube and do some scrambles. Everything is exactly the same as the previous 4, just construct each edge and push it into the top layer.

This is enough to scramble a 2x2x2 Pocket Cube and a Rubik's Cube but for the 4x4x4 and bigger cubes we need to reach the inner layers too. On even layered cubes, these parities are noticeable during the OLL and PLL stages, hence the names OLL parity and PLL parity. There are a few cases for 5x5 where the last bar will be harder to construct without disturbing your progress, but there shouldn’t be any that are too difficult that they require commutators (for 6x6 and 7x7, you may need commutators to solve specific centre pieces). On official WCA competitions they use not only the classic 3x3x3 Rubik's Cube but other cubes like the 2x2x2 Pocket Cube, the 4x4x4 Rubiks Revenge, the 5x5x5 Professor's Cube up to the 7x7x7 cube.

PLL Parity becomes noticeable at the PLL stage due to the permutation of the top four edges upon completion of the orientation of the last layer.