Jan 18 2016

Customized Chinese Checkers


cc-board full close

This project was a pretty quick one. Since we have six people in our household, I wanted to personalize a six-person game. The first to pop into my head was the classic Chinese checkers. I had originally planned to have each of us make marbles out of polymer clay colored to each one’s liking. Maybe we’ll do that another time. We went with our pictures instead this time.

The Pieces


First we bought some glass pebbles from the dollar store (the consistency of size and the clarity weren’t great, but the price was). Using powerpoint, I circularly cropped headshots of each of us, sized them to be a bit smaller than the cross section of the pebble, and printed them. I could have gone smaller; the pebble magnifies and the smaller version may look better. If I would have reduced the photo size I might have made a colored ring around the picture to make it stand out. I’m sure a photo-quality printer would have been nice too.

From there I just glued the pictures I had cut out onto the pebbles with white glue.

Especially because we have two girls who look very similar and, at a glance, it wasn’t so easy to recognize the images, I wrapped each with a small rubber hair tie of a favored color. I used a little smear of glue on them as well.

And that was it for the “marbles;” some tedious (60 total pebles) cutting and gluing and such but nothing challenging.


The Board

I used this template to make the board. I made the diameter of the circle match the size of the larger pebbles. I used powerpoint and simply created a circle the right size and then resized the template to match. I also cropped the image to just one point of the star.

I then taped it on my cardboard and made shallow cuts with a utility knife for all the circles. I moved the template, overlapping one row to make the next star point. And again for all six points.



I peeled the top and corrugation layers from the cut circles. I then lined out a hexagon for the top of the board. My top cardboard piece was pretty flimsy, so I glued it to a slightly larger circle, making the corrugation of the layers perpendicular.

And it was done.

We tried to play a six player game with it, but the 2 year old wasn’t interested for too long and eventually siphoned off the five year old and later then six year old. Maybe in a couple more years.

Jan 10 2016

Chess Board Snake Cube


I had made some puzzles that were predesigned, that is, someone else had already made the arrangement, but with a bit of personal flair. For example, a soma cube with Rubik’s coloring and the modular origami bedlam cube. After making a pentomino chess board and a 3x3x3 snake cube out of paper pulp, I was looking for another puzzle to build. (Here are some other projects I’ve made)


rubik colored soma cubemodular origami bedlam cubepentomino chess boardpaper pulp snake cube 3x3x3

I thought about the 4x4x4 snake cube and quickly realized that the 64 cubelets could potentially also make an 8×8 square.

I searched online for anyone who had done it. Finding no one, I set my mind to finding a way or finding that it was impossible.

How could I figure out a snake arrangement that could form a square and a cube?

Huge Possibilities

Calculating the number of different snakes from 64 cubelets was easy enough. There are 3 kinds of cubelets: the ends, the straights, and the turns. There are 2 ends and then each of the 62 remaining could be straight or turn, giving 2^62 (or 4,611,686,018,427,387,904, over four quintillion) different 64-cubelet snakes. Of course most of them wouldn’t make a square or a cube, let alone both. With some research I found that a 4x4x4 had  27,747,833,510,015,886 possible Hamiltonian paths. This counts rotations and reflections as unique, which was not of concern to me, so I was only looking at about one quadrillion possibilities. As for squares, I only had to look through  3,023,313,284 (really only about 378 million discounting rotations and reflections). Once I discovered these numbers, I knew a few things.

I was going to need to write a computer program (and I’m no programmer). I should start with finding paths on the square (it’s the smallest big number). If there wasn’t any overlapping solution, it would be incredible (maybe there’d be an article to write on that).

As with most work, the write-up makes things sound a lot smoother and more orderly than they really were. There was massive wasted effort exploration coming to the conclusions I did. It required a lot of learning split up over a long time (I’m getting a PhD in education policy, not snake cubes).

missing puzzle pieceIt ended up being possible to find a snake arrangement that produced a cube & square. However, in my pursuit to built the first one I found I left unfinished another aspect of the search I would love to figure out: how many solutions are there? I would love to have a complete map of all the snakes that solve both ways and all the different ways each snake solves. It is possible that one snake arrangement might have, for example, four cube solutions (ignoring rotation/reflection) and ten square solutions while another snake has unique solutions for both. Of course, with the carving out I’ll discuss later, another layer of matching is introduced that would make multiple solutions unlikely. But for snake cubes themselves it would be interesting to list the snakes by solutions spaces.

I would also be interested to see what percentage of hamiltonian paths for the 8×8 and 4x4x4 make it onto the list. Based on my work so far, I’d say it’s a small percent.

8×8 Hamiltonian Path Creation

So I wanted to find hamiltonian paths for the square. But with billions to work with, how was I to search all paths without missing, repeating, or wasting time?

Here’s a video of the algorithm that I finally landed on for finding hamiltonian paths on the 8×8: (I’m kind of a slow talker, so you might want to watch at 1.5 or 2x)

Basically it adds a square at a time by
Finding the neighbors of the end of the path
removing any options that obviously don’t work
and stepping back when no options exist.
It is a depth-first search, trying to find the longest path before moving to the next.

You can also watch this video for a walkthrough of my code.

Snake Creation

The algorithm made the snakes alongside the square paths. Sometimes different paths used the same snakes.

Cube Checking

After finding a bunch of paths on the 8×8, I needed to see if any of the snakes formed by those paths could also make 4x4x4 cubes. I suppose I could have made the program run each 8×8 as it came along but I didn’t, perhaps the batching saved some computation because I removed repeated snakes (those with different paths but same snake configuration).

Basically it functions much like the 8×8 builder but selects the options based on the cubelet type. It starts with the first snake and the first position. It tries all the options, tracking any full paths produced. Then it proceeds to the next position and so on. Then proceeds to the next snake.

Finding the One

After making a whole bunch of 8×8 paths, I grabbed a few and eventually found a snake that fit the criteria. I double checked it to make sure it worked. Below is one solution in each form (I’m not sure if there are others for this particular snake)

Snake: 3, 1, 1, 2, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 1, 1, 2, 3

8x8 solutioncube solution

Chess Board

It is very common for snake cubes to utilize a checkered pattern. Here I had a snake cube that could form a chess board in its 8×8 form. I thought it would be especially awesome if in its cube form all the chess pieces would fit inside. For this to be worth it to me, I needed the pieces to be appropriately sized relative the board squares and I needed all the faces showing on the cubelets in both forms to be smooth.

Eventually I came up with an arrangement that seems to work. I learned 123D Design so I could construct a virtual prototype and I’m now working on a physical one. After a rough draft I may have to produce a high-quality one.

Snake cube

Snake Cube Chess Board Snake Cube

This relatively simple idea became a consuming project that led me into learning from several fields.


Here’s my code

Here’s my design

Jan 4 2016

DIY Find the Differences with Bitstrips

Bitstrips Find the Differences

Ada, who just turned 5, wanted me to make some ‘Find the Differences’ puzzles for her. I decided that Bitstrips would be a great fit for this project.
It’s pretty easy to do.

1. Sign-up for bitstrips and log-in.

2. Create some characters.

family bitstrips

This is pretty straight forward. Here is one basic tutorial. My kids love making all kinds of characters, but I thought having their characters in the image would be more interest keeping.

3. Create ‘Find the Differences’ puzzles

Find the Differences

Create a two panel comic.
Design the first panel using a lot of adjustable objects.
Use the duplicate panel button
Make alterations in the second panel. (You may or may not want to keep track of the changes)
If the want to reuse a comic, you can remix after you save.
It’s that easy.

Here is a basic tutorial video.

We’ve also used Bitstrips to make bookmarks, coloring pages and writing prompts, and seating markers.

seat markers

table settings

arrangements counter

Mar 6 2015

Happy Birthday

Happy Birthday
You know I love a surprise party, especially if it’s themed. This year, playing off 32, which is how old Tiffany is turning, I went with a 2^5 theme. In this context that means packing in 5 “party of two” dates in one day.

Thank you to all the people who took care of the kids so we could get out so long.

Date one:
Lunch at Nitty Gritty (the Official Birthday Place)
and a game at I’m Board!

Date two:
Swing by Sonic on the way to Fired Up Pottery

Date three: Strolling to Picnic Point and out onto Lake Mendota for the sunset

Date four: Madison Museum of Contemporary Art

Date five: Dinner downtown and home with no kids

I love you Tiffany

Feb 14 2015

Happy Valentine’s Day

To Tiffany. I love you (nerdily).
Happy V-day

Feel free to copy the following into the wonderful Desmos Calculator:

$\left(\frac{2\sqrt{2}\cos \left(t\right)}{\sin ^2\left(t\right)+1},\frac{2\sqrt{2}\cos \left(t\right)\sin \left(t\right)}{\sin ^2\left(t\right)+1}+1\right)$

$\left(\frac{3}{2}\cos \left(\frac{7}{4}t\right)\cos t,\frac{3}{2}\cos \left(\frac{7}{4}t\right)\sin t-\frac{5}{4}\right)$

$\left(4\sin \left(t\right)^3,3\cos \left(t\right)-\cos \left(2t\right)-\frac{\cos \left(3t\right)}{2}-\frac{\cos \left(4t\right)}{6}\right)$

Domain: (0, 50) is sufficient.

Aug 12 2014

Cardboard Bookshelf

Shelf models
The planets aligned a couple weeks back. My wife was out of town for a couple days, which meant lonely evenings and less concern for tidiness: a great combination for a large craft project. This coincided with move-in/out weekend at my apartment complex, which equated to substantial amounts of cardboard in the recycling bin, which I gladly rescued.
We have been needing a solution for the toys that find themselves downstairs. Upstairs we still use the Tetris shelves I made a couple houses ago. They are still holding up.
I’ve been on a bit of a cardboard kick lately [see some previous posts].
I figured the cubbie-hole style would allow the cardboard to hold more weight than trying long shelves. The holes needed to hold toys so I made them 14-inch cubes (theoretically; more on that below). I estimated that 4 corrugations thick would be about 5/8 inches and would be sufficiently strong. You can see from the sketch the form of the six internal interlocking pieces and the four external pieces.
Shelf sketch
I wanted to alternate the locking because I thought it would be sturdier, but I didn’t anticipate how difficult (but clearly not impossible) piecing together would be.
Most of my pieces ended up a bit fatter than 5/8 because I found most the large boxes used doubled corrugation. Therefore I ran the doubles on the outside with matching direction and used a single in the middle with opposite corrugation direction. I think the design would hold the pieces together with no glue, but gluing makes cutting much easier. I used hot glue, but I wouldn’t recommend it. Some white or wood glue would be better, I think, but I didn’t have it on hand (plus, it dries more slowly). To keep the shelves square I needed to fix in two bracing pieces 14×14 inches with 5/8×2 inch tabs, as shown in sketch. I ended up just finding some very stiff cardboard and going with a single layer (same for the front pieces (though the front is not so stiff)). The back pieces I glued in. I added some glue to the external boards as well. I think longer connectors would have helped and could be trimmer later if need be.
Finished Unfilled Shelves

back brace connectionback brace

end connectioncorner connection

alternating interlocking boards
The personalized covers were fun but can be a bit tricky to put on. I wanted covers so the kids could have some autonomy in storing their junk (they collect a lot of junk) without Tiffany and I needing to look at it. Because my boards were thicker than 5/8, I cut the front squares 13 7/8 so they would fit better and notched the boards ¼. The big kids chose their fonts from a list of stencil fonts and told me the color they desired (I had to mix the Princess Else-inspired light blue).
Finished Fill with covers
Plus, if you happen to have six covers, you can show how two consecutive triangular numbers add to a square number.

Jul 20 2014

3 Cardboard Storage Creations

Whereas some of my projects span several days, weeks, or even years (from concept to completion), the 3 designs featured here hardly take any time at all if you have cardboard, packing tape, and something sharp.

Depending on the care (read: time) one wants to take and the aesthetic desired, cardboard projects can greatly range in look. Don’t write these off just because of the quick and dirty examples here.

1. Paper Organizer
This project went through two iterations. In the first the shelves were only taped in. After overloading it with projects and the occasional child using it as a ladder to get to the counter, it needed some repairs. The second version has slots cut in so the shelves poke through and are more stable.
Cardboard Paper Organizer

2. Toy Food Cabinet
The kids had a bunch of small items that needed stored such as food and dishes to go with their toy kitchen, so I put together this cabinet and drawers. It has held up about a year so far.
It has closable cabinet doors on top that open to two shelves. The hold by tabs cut into the doors that match to slits in the middle shelf. The bottom housing two removable drawers.
Cardboard Kid Kitchen Cabinet and Drawers

3. Bed-side Table (x2)
The first one was made for Tiffany to put her glasses and bedside books and whatnot in. We had less than a foot of space beside the bed so I put this together to fulfill the need in the space we had. It has two removable drawers in front that fill half the depth. The top of that section is reinforced so a drink can be placed on it. The back half opens from the top and provides a nice space for larger items.
Bedside drawers from cardboard
Later my oldest daughter wanted one of her own. She didn’t have the space restrictions, so I opted for a slightly larger version made from a diaper box. That way I had less cutting. I also tried to size the drawers more carefully.
Cardboard drawers frontbedside backcardbord bedside drawers

Jul 16 2014

Fibonacci Sequins Cube

Fibonacci Sequins 1,2,3
As you may know from the previous Modular Origami Bedlam Cube post, an anniversary a couple years ago was Fibonacci themed. While exploring gift ideas to make, I thought of or stumbled across (I don’t recall, but I’m certainly not the first to think of it) the play on Fibonacci sequence, Fibonacci sequins. I decided to put this to work on a cube I had already made for another purpose.
The cube is an old t-shirt cut into two 1 unit by 3 unit rectangles and held in the shape of a cube with fabric glue baseball-style and dryer lint stuffing.I made them mostly inside out like one would if one was sewing a pillowcase or something.
The die features “1,2,3,5,8,13” in glued on sequins. I opted to start with 1 and 2 because it allowed me to get to the 5, 8, 13 portion of the sequence, which was the important part for the anniversary.
Fibonacci Sequins 5,8,13
Because half the numbers are higher than the traditional 1-6 die, you might try it for games you want to speed up. It is also soft, so it can be used when harder dice might be too loud.

Jul 13 2014

Magic Square 15-Puzzle Bookshelf Covers

Magic Square 15-Puzzle Bookshelf on Make A Gif

Finally, after at least a couple years after the concept popped into my brain, I have completed the Magic Square/15-Puzzle Bookshelf Covers. Before we moved to Madison we picked up this Ikea bookshelf. Long before we got one, the 4×4 design immediately led me to think about the two aforementioned number puzzles that utilize such a grid.
I collected a whole bunch of cardboard scrounging through our apartment’s recycling bin. Each square is two layers with the corrugation crossed to increase the strength and magnets glued to the back.
Square back
I wanted a solution to attaching them to the bookshelf without damaging it, so they could be removed later if we wanted.
I finally decided to go with can lids with holes poked through like buttons, stirring straws affixed to the back to better hold them in place, and then tied around the back with fishing line.
can buttons
Here is a magic square arrangement.
magic square
And here’s a solved 15-puzzle position:

Jun 16 2014

Paper Pulp Pentomino Chess Board

Back when Asante was starting to get into chess, I decided to try out this riff on my theme of paper pulp and puzzles. Similarly to the Bedlam Cube (because they both have 64 units), the 8×8 pentomino chess board uses 12 pentominoes and one tetromino, a square in this case. The difference is that because these pieces are effectively 2D, there exist only 12 pentominoes total. Also, because they need no specific thickness, I made these pieces only half as thick as the pulp units featured in the soma cube and snake cube. This allowed them to dry much faster.
I checkered it with a small amount of watercolor paint. It is made out of paper, so getting it even moderately wet is a bad idea (unless you are recycling it into something else).
This is a challenging puzzle without the checkering, but with checkering it can be brutal. If you are just looking for a quick game of chess, you may want to memorize or write down a solution.

To go along with the board I made some abstract chess pieces from a mix of paper pulp and homemade playdough. The playdough serves two purposes: it shapes better and gives a bit of weight. Also, it seems I set these up on the other side of the looking glass, because the queen and king have swapped places.

Jun 14 2014

Modular Origami Bedlam Cube

Tiffany and I celebrated our 8th anniversary last year. Because we were married May 13th, the Fibonacci sequence popped into my head (particularly the 5,8,13 part). So to commemorate this special day I romantically created a Modular Origami Bedlam Cube. I choose the Bedlam cube, not to represent the state of our household, but because it is a thirteen piece puzzle made predominately of pentacubes, thus achieving the 5 & 13. Additionally, I wanted to embed the Fibonacci sequence, so I created a clear plastic ‘0’ piece using the single tetracube, then created the other pieces in color groups for the next numbers in the sequence. Each piece, besides the ‘0’ piece, was created using a modular origami technique from mini-post-it notes. The number of modules needed matches the number of faces of the pieces. Putting them together is pretty straightforward but takes some practice, especially for the inward corners. I found using a straight pin to push from the inside helped shape the pieces.
The modules are a great thing to do waiting at the bus stop (or proctoring an ACT) because they easily slip into your pocket.
If you’ve mastered the soma cube and snake cube, this 4x4x4 puzzle is a good next step. This great resource can help if you get stuck and just need a solution. It also alerted me to the Big Brother cube, a very similar puzzle which uses a different set of 12 pentacubes from the 29 possible that I have yet to try.

Happy building.

Jun 12 2014

Snake Cube

This paper pulp snake cube I actually did finish back in Philly.
I made 27 paper pulp cubes. I’m sure you could make them more uniform than I did but they get the job done.
I then drilled holes in all of them; some directly through and some on two adjacent sides so the holes would meet. To figure out how many of each to drill, look at the picture of the unwound snake. If the cubelet forms a corner (that is, the snake changes direction at that cubelet) then drill two adjacent sides. The others, including the ends, drill through.
I then created a chain of rubber bands to feed through the holes using a pipe cleaner as needle. The corner pieces can be a bit tricky. If the pipe cleaner can’t get you through the bend you may have to drill a little more diagonally.
Also, a note about the drilling. You can shred your paper pulp cubelets pretty easily, so I recommend a fairly small bit to start and have it spinning when it hits the cube. You can always wiggle the bit a little to widen the hole.
I also recommend building the rubber band chain as you go so the sizing is right. You will probably want it tight enough to hold together but loose enough to spin and stretch some without fear of breaking. I safety pinned the end of the chain so it couldn’t slide through the hole. Also, to ensure that your snake can coil into a cube (3x3x3 cubelets), thread the cubelets in careful order, which you can match from the image.
After they are all threaded, safety pin the other side and you’re finished. You could fancy up the exterior, but I didn’t.
Simple, fun to make, and fun to play with long after.