5.AG. RUBIK'S CUBE AND SIMILAR PUZZLES I have previously avoided this as being too recent to be covered in a historical work, but it is now old enough that it needs to be covered, and there are some older references. Much of the history is given in my Notes on Rubik's Cube and my Cubic Circular. Jaap Scherphuis has sent me a file of puzzle patents and several dozen of them could be entered here, but I will only enter older or novel items. Scherphuis's file has about a dozen patents for the 4 x 4 x 4 and 5 x 5 x 5 cubes! See Section 5.A for predecessors of the idea. However, this Section will mostly deal with puzzles where pieces are permuted without having any empty places, so these are generally permutation puzzle.
