I first saw the concept of this puzzle in a wood working project book geared towards kids and parents working on projects together. I liked the idea enough that my son and I built one out of very thin plywood. That first puzzle was a two-layer design like this one, but even less complicated as we where hand cutting the plywood with a coping saw. That and my son had the attention span of 6 year old.

As I began writing this Instructable I researched if this puzzle had been introduced on Instructables before and it has. I found two examples: One made of Cardboard and one of laser cut acrylic, and both published by “kiteman” back in 2006.

The nice thing about this project is that you can make it as simple or as complex as you desire. It can be made of many materials: cardboard, wood, plastic, etc. It can be one level or as many levels as you wish and the material can be transparent or not. My puzzle was designed to solve blind and to not see the coin from the time it enters the puzzle until it leaves the exit. However I ran out of blue filament and finished the top with a semi-transparent filament. So you can see enough to help solve the puzzle. I may yet give the project a coat of spray paint to hide the coin from view, but it is fine just the way it is.

Step 1: Supplies and Safety Warnings

Supplies:

3D Printer, Laser cutter, saw, knife. All dependent on the materials you chose.

Glue to bond the layers together. (I chose 5 minute epoxy as it works well with PLA)

A dime

Design software and/or Graph Paper

Pencil

Safety Warnings:

This is the safest project I have done is a long time. Avoid long term exposure to 3D printing fumes or glue vapors. Other than that I do not see much that can go wrong here. A different story if you are making yours out of wood and using saws, knives, drills and the like. If so then please use all the proper safety equipment.

Step 2: Design Ideas

Begin by deciding how big your end product will be and how many levels it will have. For this puzzle I decided to make a two-level version and 3D print it. I will show you the lay out all the way from design to printing.

This puzzle appears to start on the upper level when in reality it drops the coin immediately to the lower level, and then it transfers it back to the upper level after a strategic flip of the box. So as simple as this maze seems it can be a complicated puzzle to solve.

Once I decided on how many levels to make I grabbed some grid paper to work out the dimensions and design layout. As I said this is the second time that I made one of these puzzles, so I already had ideas and experience to draw from so it did not take long at all to put pencil to paper. I measured a US dime so that I knew how big my channels needed to be. I chose 20 mm to allow easy movement of the coin within the puzzle and about 2 mm channel height.

Because I hit pretty close initially on the scale of my drawings to the dimensions of my 3D printer's build platform it was very easy to transfer these from drawings to Tinkercad for the design phase. I did print my layers thicker than necessary which is a waste of filament, but if you are making this out of other materials my dimensions may seem thin at 4.5 mm per level.

Step 3: Changes to the Design

After printing version "one" I decided on a few quick easy changes for the next one in order to make it just a little tougher to solve. See the pictures and notes above for the changes made. These changes will be the 3D files that are shared here and not the ones that I 3D printed for this Instructable. The designs that I printed are shown in the previous step in notes and screen shots and in this step as photos. Check the photo notes for changes made.

Step 4: Assembly and Solution

After printing I glued the layers together with 5-minute epoxy making sure that the glue did not run into the channels that the dime needs to travel through. Because this would potentially impede travel of the coin thus making the puzzle insolvable.

Here is a video of the puzzle in action. With this video and the diagrams shown it should be easy to solve this puzzle. To make more difficult version you may increase the size, add more levels, or add more flip-overs of the box.

I attached the stl files in this step. If anyone uses these files please confirm that they work with your program. My computer saves stl files as .dremel files and I do not know if they are universal stl files or only recognized by the Dremel 3D20 Ideabuilder printer.

Step 5: Conclusion and Bonus Material

This was a fun little project that I hope that you enjoyed. I would eventually like to make a "perfectly square" version of the maze where the coin enters the top and exits the bottom. If I did this using the dimensions of this puzzle (145 mm x 145 mm x 4.5 mm) there would be roughly 33 different levels and if done right the coin could be lost in the cube for days.

You can see in the photos that the maze can be made up of words, shapes or images as well.

If I ever do make such a creation as the cube I will certainly add it to this Instructable when complete. As seen in the screen shot above the large puzzle is well under way, but with each layer taking about 2 hours to print it could be awhile before I get around to printing this one. I do know to that I will have to provide a solutions map for the "cube" if it ever does get printed as it is much to complicated to "solve" from memory. I added a by-pass to this design that can be blocked off to take it out of play. This by-pass allows the puzzle to be solved with just 5 levels of play. I will make a plug to insert into the exit slot to take it out of play. I added the bypass because I thought it would be fun to solve the puzzle in a few quick moves and then hand it off to someone to spend hours or days solving. I also will print this one in a semi-transparent material so that it can at least be seen what level the coin currently is on, otherwise I believe that it would be nearly unsolvable and require just pure luck to exit the coin.

Please let me know if you have any questions or comments.

Thank you, Schockmade.