The puzzle consists of six equally-sized half-cube blocks that fit into a box in only one way. It's simple, but deceptive enough to entertain people for a while until they figure it out.
This is not an original idea of mine. It is based on a puzzle I saw at the Pacific Science Center in downtown Seattle, and I thought it would be fun to duplicate it.
This is a quick project that can be done is just a few hours. Take a look, and then go make one for yourself!
Step 1: The Solution
So here it is. Trust me, it's not as easy as it looks!
Step 2: Make the Blocks
The actual width of the sides of 4" by 4" boards is 3 1/2", so I needed to cut pieces that were 1 3/4" tall to get the desired half-cube shape.
I set up a stop on my miter saw and cut six pieces.
Another simple option would be to use pieces of 2x4 studs. Since they're actually 3 1/2" by 1 1/2", you would need to first trim the width of the board down to 3", and then simply cut off six square blocks.
Step 3: Measure for Box Opening
The box should provide just enough wiggle room that the blocks can be removed easily. I'd suggest making a box with an opening 1/8" to 1/4" over the size of the blocks when stacked in the completed puzzle configuration, like in this photo.
In other words, the height, width, and depth measurement of the box opening should be just a little over 1.5 times the length of one block.
For me, that meant making a box with an opening that was 5 3/8" all around.
Step 4: Make Box
The bottom piece is 5 3/8" square, and the lid is 6 7/8" square.
I assembled my box with glue and brads. A simple box like this can be assembled with just glue, or with nails or screws. If you use screws, be sure to pre-drill your holes so the wood doesn't split.
Step 5: Touch Ups
If you have access to a router table you can use it to round over the edges of the blocks as I have done. If not, just sand all the sharp edges off the blocks by hand or with a power sander.
Step 6: Finishing
I stained my blocks with oil stain and then sealed them with shellac. When the shellac was dry, I gave them a light sanding and then applied some paste wax.
For the box, the inside was finished basically the same way as the blocks. For the outside I used spray paint, shellac, stain and wax to get the look you see. I was experimenting with different things and the finished look of my box was mostly an accident, but I like the way it turned out.
There are so many routes you can go with wood finishing, and everyone has their opinions on the matter. Sometimes it's fun to just experiment and see what happens. Make sure to have adequate ventilation!
Step 7: Hardware
You could add handles and a clasp of some kind at this point, but I chose not to.
I originally planned on putting little rope handles on mine, and had drilled holes in the sides to put them on. But I ended up not liking the way they looked and decided they weren't really needed anyway, so I took them out. The holes were plugged with dowels that were then stained (second photo). Now they just add a little character, which is nice.
Step 8: Final Thoughts
So if you have a visitor over and they ask "Hey, what's in the box?", don't say "It's a puzzle," until you've dumped the pieces out. If they open it up knowing it's a puzzle they'll pay attention to how the blocks are oriented!
Well, that's it. Thanks for taking a look.
If you make one, post a photo in the comments. I'd love to see it!