This is a functional clone of Dayan/MF8 Crazy Tetrahedron series puzzle. Dimensions differ from the original puzzle, so parts are not interchangable. However it still good to configure any puzzle of the series.

There are 3 types of the faces:

• 0 - inner pieces are fixed and do not rotate with face rotation (only outer pieces move)
• 1 - both inner and outer pieces move
• 2 - there is no inner circle, whole face move

Combinations of different type faces give differrent puzzles in the series. Please refer to the configurations table to select the puzzle.

Unlike my previous crazy puzzle where I glued pieces of different color (corners and edges), this time I made a disassemblable design. You can reconfigure edge and corner pieces attaching different configurations of subparts according to selected configuration.

Outer Edges pieces are assembled using a short (6-8mm) pieces of bamboo stick 2.5mm diameter. Corners parts are attached to triangle prism-shaped link piece with 5mm piece of a toothpick.

The tricky part is corners assembly as parts should align without gaps. First you should glue pairs of corner subparts (left and right). Then faces that should aligh to other corner pieces should be sanded a bit, not too much, just to remove roughness. If your printer calibrated right you should get 3 pieces that align well.

As for core. I used the same idea of composite core I used in crazy 3x3x3. This time it was not so good, as spherical parts have 60 degree inclined faces. but even though core is still pretty good.

I printed the puzzle as stickerless, but stickered version is also possible. Just print everything in one (preferably black) color.

This time I decided not to sand/polish pieces. This saved me quite a lot of time. I used sanding to remove only obvious roughness.

Puzzle requires 4 pcs springs and 4 pcs M3x20 screws. Springs should be pretty strong, otherwise puzzle will be too loose. Rubick's Cube springs and Screws should work well.

I am pretty happy with how this puzzle turns. Everything tuns well, even 0-faces. Puzzle is pretty stable, does not explode. It is sometimes catchy, but not more than I would expect from a 3D printed twisly puzzle.

Here is a video how this puzzle moves and also how to assemble edges and corners
https://youtu.be/zyr9oBCyFYM

UPDATE 1-Nov-2016
I just uploaded couple improvements in center pieces.

Caps sometimes popped out on fast turns. So I changed the design and added small hooks. These hooks tighten the cap to the center piece, and at the same time it allows to remove cap easily.

Another issue is center pieces pins. There is not too much plastic near the pin and it is easy to break the piece here. So I added some reinforcement by gluing a piece of filament across layers.

Use v2 STL versions of center pieces. I left previously designed files just in case.

One more issue I solved is light plastic (white, yellow) quickly gets dirty. One of the solution would be to print puzzle in black and use stickers. Since I already printed mine I applied some polyurethane varnish to visible faces. The puzzle now looks glossy and does not feel like a printed one - more like a factory produced.

I played with the puzzle for 2 weeks after my improvement. It still turns well, nothing breaks, look awesome and does not get dirty.

I am open for feedback. Please leave comment if you think something could be improved. I am also looking forward to see your makes