* Patio Block *

* 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