3d1a) Competitors may use textured puzzles with different textures on different faces. Each face should have a distinct colour, to aid in scrambling and judging.
3d2) The colours of puzzles must be solid, with one uniform colour per face.
3h) Modifications that enhance the basic concept of a puzzle are not permitted. Modified versions of puzzles are permitted only if the modification does not make any additional information available to the competitor (e.g. orientation or identity of pieces), compared to an unmodified version of the same puzzle.
3h1) "Pillowed" puzzles are not permitted.
3j) Puzzles must be clean, and must not have any markings, elevated pieces, damage, or other differences that significantly distinguish any piece from a similar piece. Exception: a logo (see Regulation 3l).