  In this step, moves are restricted to the subset <(l'rR),(rR),U>. l can be used in emergencies. ;) This step is completed with the same technique as the last four centres in the reduction method. However, you are restricted to not destroying the 1x3x4 block. Despite this restriction, solving the four centres can be just as fast - you'll find you're simply doing (l'rR) / 3R instead of x. |