ABSTRACT
Picture the challenge of a Rubik’s Cube. To solve the puzzle, you have to rotate the pieces until the nine squares on each face show the same color. This may involve working on more than one face at once. Perhaps you have to move two green squares out of place and park them somewhere else while you put a red one where it belongs. Yet even with all the variety of possible moves, there are certain constants. The center square on each side is fixed in place and connected to the center square on the opposite side. No matter what you do, the center squares stay in three sets of opposites. Everything else rotates around them.
