Devil's Key / Devil's Cross - Interlocking Blocks

Introducing “The Devil's Key”, or how some call it, “The Devil's Cross”. This is a simple yet challenging to build shape. It's a puzzle that originates from a small part of Romania, from the mountains of the northern Transylvania region. As you'll soon learn, this is more than just a model. This is history.

The story of Moș Pupăză

This was originally a puzzle created by a shepherd and woodworker named Moș Pupăză. One day he was sitting around, watching his sheep, and got bored. He took his knife and approached an oak tree. He bowed before the tree, asking for forgiveness, and promising it that he would bring life back into it. Moș Pupăză then took some branches, and started to sculpt them into various pieces. Then he tried to shape them in such a way they would interlock. The pieces, when arranged correctly, make a hole in the center where a “keystone” (a simple stick) could be inserted to lock the whole thing up. 

He spread the word of what he invented, showcasing his ingenious woodworking skills to the entire Maramureș county. He started selling this new thing he made to tourists visiting him and his tiny village, making a living out of this. In his words: “Ar fi simplu de povestit, dar greu de făcut. Nu ușor se desface, dar și mai greu se pune la un loc.” (It would've been easy to tell, but harder to make. It's not coming apart easily, but it's even harder to put back)

Moș Pupăză passed away on January 3rd 2017, one year before I discovered his inventions, and his story. He was buried in his own private cemetery which he built for himself, on a private piece of land in his village Valea Stejarului. On the two plaques above the entrance he wrote the following:

“Travelers all stop/And think about the hour of your death/The cemetery is a big city/But it has nothing to sell/There is nothing to buy/Only what you give yourself”

“Attention travelers,/Those of you who are travelers in this world/To your grave, your friends and relatives lead you/From there on, facts give answers”

Details on The Devil's Key

The story of Moș Pupăză

The base concept

Being strongly inspired by this little piece of local culture, I made it digital, a 3D model. The original Devil's Key had simple, rectangular chamfered pieces. Over the years, another version of it came out, a spiked one. This caught on even more than the original one. So I decided to make both of them, keeping both the popularity and the origins of this puzzle.

The basic concept is simple: arrange and interlock the 6 different pieces to create the star/key/cross. There is no trick! It's just a game of shapes. When you introduce the keystone last, the whole shape should be extremely stable and strong in all directions, making it essentially one solid piece.

Of course, this can be modified in any way shape or form, making the pieces wavy, interlock in different ways to create even more extravagant shapes. This is just a basic shape, that can be infinitely modified and improved upon by you, the 3D printing community. I strongly encourage you to make some remixes of this awesome little trinket, sharing in any way you can the story of Moș Pupăză. May he live on forever.