Bridges of Xibalba


It seems to have become almost a Christmas family tradition now, but for the last few years I have made a wooden puzzle for my brother as a Christmas present. There are two main reasons for this; first because I never really know what to get him, and second because I really like making stuff out of wood 🙂 So this Christmas I wanted to make a puzzle which would challenge both of us (Me in terms of building it and him in terms of solving it!).

I spent a bit of time in the weeks before Christmas looking on the internet for ideas of puzzles to make which were not the stereotypical “Put-it-back-together-again” type, but rather something that was both visually appealing but also (supposedly) challenging to solve. I eventually settled on a puzzle called “Ziggurat Square” which I found on a website called Creative Crafthouse which I believe is an American company specialising in wooden puzzles. I’d like to say I made my own version of the puzzle but in truth I simply copied their design (Trusting that it was actually solvable!) with only the addition of a lid and a change of title to help prevent my brother from googling a solution 😉

The idea of the puzzle is that all the pieces must be fitted into the box (Pretty hard in itself) and all towers must be connected by at least one bridge. There are of course lots of possible solutions but only 2 (apparently) where each tower is connected by 3 bridges. This is the real challenge and one which I hoped would prove difficult for my brother to solve.

As always I initially designed the project in my computer using Maya (A 3D modelling package) to figure out sizes and angles etc. Once this was done I was far more confident in the design and how to build it.

I initially built the project inside the computer to help figure out lengths and angles

Then on to the woodwork. I started with a single plank of Iroko which I had initially bought to be used as part of a garden table project which never got started. I squared the board on the planer/thicknesser and was then ready to start cutting pieces.

Board of Iroko planed and squared

I set up my bandsaw table to 20 degrees and cut a few strips off the board, being careful to measure the sizes accurately and use the fence in order to keep to the correct lines. Normally this would probably be done on a table saw, but as I don’t have one, the band saw did the job OK. It did leave rough edges, but these were easily sanded down.

Bandsaw table set to 20 degree tilt

Cutting long strips on bandsaw

These were the strips that I cut on the bandsaw

You can see from the photos that there were a few strips. The thicker of the 3 was mostly spare with the exception of needing to cut the sides of the box from it. The middle size was for the towers themselves and the thinnest piece was to cut all of the individual bridges. All of this cutting was done on the mitre saw. When cutting the towers the saw was set to a 20 degree compound angle to match the 20 degrees cut on the bandsaw

Mitre saw set up for 20 degree compound cuts

All the towers cut to size

Then to cut the bridges I reset the mitre saw to a straight 90 degree angle and cut all of the individual bridges.

Mitre saw set to 90 degrees for cutting bridges

All the towers and bridges cut to size

The only other thing at this stage was the sides of the box which were again cut on the bandsaw. At this point I did not cut them to final size as I wasn’t yet sure of the final box size. Sanding the pieces would alter the overall size a bit and I wanted to wait until all the pieces were sanded and glued.

Edges of the box before sanding and final cutting to size

Sanding was probably to most tedious part of this project, with every single piece needing to be sanded. Also I had to be careful not to over-sand in case the angle were to be altered and then no longer fit correctly. All sanding had to be done by hand simply due to the size of the pieces.

Sanding all of the pieces took a loooooong time

Next was gluing, and this also took ages…mainly because I didn’t have enough clamps to do more than 4-5 parts at any one time, so all in all it took about a week to do. Clamping was also pretty tricky due to the angles of the pieces involved. Fortunately I had plenty of off-cuts which were 20 degrees on one side and 90 degrees on the other, meaning I could use them to brace my clamps correctly. Hopefully you can see this in the image below.

Gluing was the trickiest part and took the longest mainly due to the fact that only a few pieces could be done at a time

Eventually all the parts were sanded and glued and I could finally test the puzzle. To my relief it seemed to work fine and also I had managed to find a proper solution on the internet which I tested and this too worked fine.

All pieces completed

Completed puzzle (but not the proper solution)

With the pieces finished I could now create the box itself. Firstly I cut the mitres for the sides using the mitre saw set to 45 degrees using the size of the finished towers as a guide. Then I glued the sides together so that I could start to think about the base and lid.

Box sides mitre cut to 45 degrees

Gluing the box edges using a couple of clamps

I have an old string framing clamp which I tried using, but to be honest, its not much use as the pressure keeps slackening off, so in the end I just used a couple of large clamps to help apply the pressure.

Next I wanted to create a base and a lid. I considered using plywood, but I really wanted to keep the material consistent in the puzzle and so decided to try and cut sheets off another board. In order to do this however I needed to attach a couple of new boards together as the boards were not wide enough to make the base. I did this by edge jointing two boards as you can see below.

Boards to be edge jointed

I flattened both board edges with my jointer plane

I applied a layer of glue to the edges, ensuring the entire surface was covered

Then I clamped the boards together and left the glue to dry for a couple of days

Now that I had a wider board I could start to prepare it for cutting strips. This is also called cutting laminations. Firstly I cut a piece off the board which would be big enough for the base and lid sections, then I used my bandsaw to cut sheets from this off-cut board as you can see.

Using the mitre saw I cut a section off the board

Using the bandsaw I cut 3 sheets from the board

The 3 cut sheets

You can see how thin the pieces were after this process was completed

Next I sanded each sheet so it was more-or-less flat and smooth. This could easily be done with a hand sander and so didn’t take quite as long as the individual pieces had done (thank goodness!). I could have passed the sheets through the thicknesser, but as I wasn’t too concerned with accuracy of the thickness I decided against it.

Sanding the sheets could be done with a hand sander for speed

Next I simply cut the pieces to size on the bandsaw. I also cut 4 small strips which would be used as the edges of the lid. These I mitred at 45 degrees on the mitre saw before gluing onto the lid underside.

The box bottom and lid were cut to size on the bandsaw

I also cut 4 small strips to use as the lid edges

The lid edges were simply mitred at 45 degrees on the mitre saw before being glued onto the box lid

The mitred lid edges

After this the puzzle was essentially built. All that remained was the finishing and logo for the box lid. In the past I have had some success with using transfer paper (The sort used to iron patterns onto T-shirts) to get printed designs onto wood. Although its not perfect, it is fairly good and saves using the services of a laser engraving company which would have been expensive. So I went back to the computer and designed the logo.

I wanted to change the name of the puzzle to ensure that a solution wouldn’t be easy to come by on the web, but I wanted to keep the idea of ancient towers and bridges. So after a bit of research i decided to base it around the Mayan culture and I came up with the name “Bridges of Xibalba”. Xibalba was the Mayan underworld and it seems quite apt and mysterious. So I based my logo and an instruction sheet around this idea. The image shows the designs I came up with:

The designs for the Bridges of Xibalba box and instructions

So once printed (In reverse because you are applying it to a surface and so needs to be mirrored) I was able to iron the design onto the box lid. I decided to draw a border around the logo as I thought it needed it. Fortunately I was able to do this with marker pen and a ruler.

Using a hot iron and some patience its possible to iron the design onto wood

I felt it needed a little more so I drew a border around the logo with marker and a ruler

The finished box lid

Finally all I had to do was apply a coat of finish and the job was done. I decided to use Danish oil to darken the wood and give it a beautiful golden colour and I then applied a coat of finishing wax as a finishing topcoat.

I used Danish Oil to colour the wood and clear finishing wax as a topcoat

The finished puzzle with instruction leaflet

I’m really happy with the way this puzzle turned out and I hope that my brother enjoys it on Christmas day. I’m sure he’ll solve it pretty quick as he’s a dab hand at puzzles but either way I really enjoyed building it.

Another photo of the finished puzzle