Before 3D printer existed,  I played with this puzzle. Right away, I made an hand made sketch of the blocks having in mind to build it one day. What a great opportunity now to built it, test the accuracy of my one year old PRUSA MK3S and submit it to the contest!

My drawing was made with Fusion 360, the original dimensions for the block are 25x25x100 mm. I made a 0,1 mm clearance on all faces sliding into each other. I printed it half scale (50 mm long) to start and want to find out if a tolerance of 0.05 mm would be enough. The result was amazing, everything fits perfectly. Then I started to change colors and add color changes to make it more interesting.

2022-01-24 Revision ( more clearance between parts)

Clearance has been increased to 0,2 mm per side on original full scale model for easier assembling. As I found out, PLA filament quality and printer accuracy can change results. I also add an image showing puzzle assembling in six steps.                                                                        -----

I came out with three levels of difficulties. The easy one is using three colors as the orange-grey and black shown picture. The intermediate level has color changes and the expert one has all the pieces the same color.

I just want to warn you, it may be an addictive puzzle. A friend came to our place the day I had printed the first set, she took them and would not talk to us until she had the correct assembling block combination. If you decide to print it, let me know the color combinations you used. Also, how quickly can you put it together?   

By the way, how small do you think it can be printed and still be able to assemble it?