Designed by Stewart Coffin circa 1975, made by Interlocking Puzzles 2001.
(8 pieces, maple and bloodwood, 2 inches square assembled)

The wood used to make this puzzle gives a clue to the solution with symmetric color shown above; the photos below show three basic steps to this solution:


It is not unique, here are two views of another solution:


Stewart Coffin, in his book The Puzzling World of Polyhedral Dissections, describes the derivation of this puzzle as starting with all possible pairs of joined 1x2x2 blocks (where the resulting 10 pieces can be assembled into a 4x4x5 solid in 25 different ways) and then eliminate the two rectangular pieces (the 1x2x4 piece and the 2x2x2 piece) to see if the remaining 8 pieces can be assembled into a cube. He then goes on to say that they cannot be so assembled, but that one can be eliminated and one duplicated to make a set that can. He also notes "an interesting pattern of symmetry" in the solution.

The 1986 patent of Guenther describes puzzles where pieces are formed from pairs of rectangular solids.

Further reading:
Guenther Patent, from: www.uspto.gov - patent no. 4,534,563