3d) Puzzles must either have coloured stickers, coloured tiles, textures or painted colours."
I have a Rubik's cube. Four of the faces have coloured stickers. Two of the faces are painted. Is it a legal puzzle?
This question asks about the meaning of "either", is it meant to be exclusive or inclusive. The authorities differ on this, for a discussion see:
http://english.stackexchange.com/questions/13889/does-either-a-or-b-preclude-both-a-and-b
"3j) Puzzles must be clean and must not have any markings, elevated pieces, damages, or other differences that distinguish one piece from a similar piece."
I assume that "similar" means "having the same shape or the mirror image of that shape". In particular, I interpret this rule to allow a puzzle to be built from a mixture of black and white plastic, providing that, for example, all the corner pieces are made from the same color plastic. Thus it is legal to combine a black and white puzzle in various symmetric ways. Examples:
(a) black center pieces everything else white.
(b) black corners, everything else white.
The reason I'm asking this is that I suspect that, with such a puzzle, for some people, it will be faster to distinguish the center pieces from the edge and corner pieces.