The pieces were designed by Seattle artist Tara Flannery, who has designed several other puzzles for Artifact. The cutting style was inspired by John Stokes III, and while this puzzle has no "whimsy" pieces per se, all the cuts are so intricate that each piece is a tiny work of art. Using Bob Armstrong's classification method, I'd say this type is interlocking (of course), with curl knobs, 1:1 contour lines, a scroll pattern, and irregular edges - and to me, it looks like a map of someplace out of Dr. Seuss!

In the completed puzzle, no adjacent pieces have the same color. This puzzle is of special interest because it incorporates the idea of a famous mathematics/graph-theory problem called the Four Color Theorem, which holds that any set of contiguous (touching) regions on a plane, no matter how convoluted their boundaries, can be colored such that no adjacent regions are the same color, using no more than four colors. (Regions that meet only at a point are not adjacent.) Although it was proven as far back as in 1890 that no more than five colors are needed, proving that only four suffice was very difficult and was only accomplished in 1976, by Kenneth Appel and Wolfgang Haken, using a computer.

Artifact Puzzles' Four Color Map Puzzle has been favourably reviewed by several puzzle bloggers, including Brian, Neil, and Allard. I had fun with it, too - it took me about an hour to complete. I found the no-adjacent-pieces-the-same-color rule helpful (colorblind puzzlers will be more challenged).

You can now own a copy of one of George's beautiful designs - it's called Frabjous and is available from the folks at Artifacture in Dallas, who sent me this 6" x 6" x 6" Special Edition Frabjous, laser cut from Acrylite Radiant Acrylic. Thanks, Michael!

This type of acrylic material reflects light in different colors from different angles and provides a fascinating display of varying hues as you move around the sculpture. The puzzle sculpture comes unassembled, in a package that includes instructions, 31 S-shaped pre-notched interlocking pieces (one extra piece is thoughtfully provided), and even a pair of cotton gloves to wear during assembly, so that you can avoid getting fingerprints in hard-to-clean places! Artifacture sells direct through various online outlets (see links on their product page), including their Etsy shop. Artifacture has produced Frabjous for MoMath (the MoMath logo, and George Hart's name, are engraved on one piece) and Frabjous is also available at the MoMath online shop. (A less expensive version is available in blue.)

It took me about an hour to assemble Frabjous. I had to recover from a false start when I realized I had been careless while interweaving some of the pieces. I disassembled what I had so far and started over, being much more deliberate. The pieces lock together by friction/pressure fit using simple rectangular tabs and notches at apexes where three pieces meet - the hold is secure, but it is possible to work the pieces apart again without too much trouble. One thing I was pleased about is that though acrylic in general seems to have an unfortunate tendency to crack at angular cut-outs, I experienced no faults in any of the Frabjous pieces even after I had attached and detached them multiple times.

During my second try at putting Frabjous together I actually found that if I ignored the included instructions and instead concentrated on the five-fold symmetry of the structure, adding five pieces at a time in symmetry around the growing assembly, I could much better ensure the correct relative placement of the pieces. Something to note is that you cannot simply create a bunch of "tripods" and then expect to link them together - it is too difficult to properly interweave such sub-structures. I took photos along the way - I think you'll agree that Frabjous is a beautiful object! I can also attest that Frabjous is a puzzling challenge to assemble, and you will enjoy a nice sense of satisfaction on completing it. My wife even let me put this one on display in the family room!

The Tanacube Too is Oskar's solution to a challenge originated by Peter Rasmussen and Wei Zhang,
to create a cubic puzzle having the classic Tangram Square dissection appearing on each face, and meeting other criteria.
You can read about the challenge at ChinesePuzzles.org/tanacube, also at George Miller's Puzzle Palace website,
and in CFF #65, November 2004, in the article Tangram Cubes: A Collaborative Effort, by Peter Rasmussen and Wei Zhang.

George Miller had offered 3-D printed copies of Oskar's Tanacube Too (at $550), but George has shut his online shop.
Oskar kindly created a Shapeways model of Tanacube Too at a more reasonable price.
Oskar then created the smaller, less expensive, Tanacube Too Small shown here.

Bill Darrah created the first solution to the challenge, called the Tanacube.
You can see Bill Darrah's Tanacube at George Miller's Puzzle Palace website, at Bernhard Schweitzer's Puzzlewood website,
and in Neil's Puzzling Parts blog entry of May 23 2011 (California Puzzle Party).
The wooden versions were made in the Pelikan workshop and originally cost $350.

Both Tanacube and Tanacube Too were entered in the IPP 2004 Design Competition,
but neither won an award - they were up against some stiff competition!

The three classic wooden vintage secret-opening puzzles Takitapart (U.S. Patent 2181116 - Boyle 1939), Pick-A-Peg (U.S. Patent 2469364 - Boyle 1949),
and Tri-'N'-Do-It (U.S. Patent 2207778 - Boyle 1940), all invented by John D. Boyle,
were issued in this boxed set, called the Masterpiece Puzzles.

Our electricity was out for over a week due to the storm on October 29th - 30th 2011. This is a shot of the trees in our back yard, bowed (with a few broken limbs) due to the load of snow on them. We lost power on Saturday night the 29th and it wasn't restored until the evening of Monday November 7th. The unseasonable accumulations of about 12" of heavy, wet snow onto trees that had not yet fully shed their leaves brought down many trees and limbs large and small and wreaked havoc with the above-ground utility lines across the northeast. The extent of the damage was unbelievable - nearly every street had issues. Fortunately, we had the option to stay with a kindly nearby relative who had power (thanks, Pat!), and the temperatures were not frigid enough to cause pipes to freeze in the unheated house.

Quadrus is a large (140 x 140 x 30mm) and attractive traditional rolling-ball multilevel maze in a gold-tinted transparent acrylic case, nicely packaged in a cardboard slipcase tray that shows off the ambigrammatic XMATRIX logo. Quadrus is also available in a blue tint, and has a smaller cubic sister puzzle called Cubus.

In Quadrus, the maze network is defined by three layers of internal latticework structures and interstices - one lattice on each large face, and a third suspended between them, with an empty thickness between pairs of adjacent layers - giving an overall thickness of 5 layers between the "floor" and "ceiling" faces. The walls in a layer are 4mm wide, and the pathways between walls are 8mm wide. Walls and pathways in a layer are arranged on a 34 x 34 virtual grid of 4mm x 4mm squares. The ball occupies a 2x2x2 space within the lattice.

The maze contains a central 12x12 square compartment - a white panel with a stylized 'X' cutout separates the compartment into a gold-framed side and a silver-framed side. Each side of the compartment has a single entrance into the maze. To solve Quadrus, one must navigate the ball from the central gold-framed compartment to the central silver-framed compartment on the opposite side, by tilting the puzzle and guiding the ball through the maze. I have found that the occasional ill-planned tilt can send the ball somewhat further than one intends, adding a dexterity dilemma to the already-considerable routefinding challenge.

This style of maze is similar to the Boston Subway puzzle designed by Oskar van Deventer for the 2006 IPP Exchange. (See Boston Subway at Oskar's website.) Boston Subway is a much smaller puzzle, but also comprises a "sandwich" of 5 layers of transparent acrylic, through which one navigates an internal metal ball from point A to B and back. Unlike Quadrus, Boston Subway requires the solver to use an included magnetic wand to move the ball through the maze. As interesting as Oskar's Boston Subway puzzle is, I find the Quadrus more convenient to hold and manipulate, and it is far easier to see and keep track of where the ball is. While less portable, it is more engaging to the casual puzzler.

For the 2009 IPP, Oskar also designed Next Floor. (See Next Floor at Oskar's website.) Produced from laser-cut MDF, this maze is formed from 5 grooved layers with four interstices. A version of Next Floor is marketed by Bits and Pieces, but unfortunately folks reported that the layers can be loose and the ball can squeeze through unintended paths or even fall out, spoiling the fun. No such issues plague the robust, high-quality Quadrus puzzle.

I found an older seven-layer version (in an eBay auction). Unfortunately it included no documentation and I am unware of its provenance.

You can read some reviews of the XMATRIX puzzles here, here, here, and here.

My own impressions? When solving a maze, I do not typically sit with the puzzle tilting it to and fro. I manipulate and study the puzzle enough to systematically create an accurate representation of the network "on paper" and then exhaustively map it out. The physical object itself becomes somewhat unimportant and is usually stored away. With the XMATRIX Quadrus, however, two things are true: It is just as much a pleasure to hold and play with the physical object as it is to intellectually solve the maze, and this is one maze puzzle that will be left out for others to enjoy rather than being put away and forgotten.

Schlitten - Constantin, Rings with red cord (?), The Squared Fish - A. Jacob, Batwing and Batwing 2 - PuzzleMaster,
Puzzle Up Nails - Rick Irby, IPP 31 Gift - Markus Götz, Hybrid 55 - Richard Hess

IPP Burr - Mr. Puzzle Australia