No Force Required – Gentle Interlock

It’s the season.  If you’re from Jersey, juno what I’m talkin bout.  And puzzlers will soon be reaping their own bountiful harvest of packages brimming with wonderful new acquisitions.  Last week was the momentous conjunction of events in the puzzleverse – Baxterweb, Cubicdissection Marketplace, Puzzle Paradise, and Mega Free Giveaways on the Mechanical Puzzle Discord (MPD).

The free giveaways on MPD have taken a life of their own and provide a means of repurposing homemade personal use copies of puzzles that would be impolite to sell.  Many are 3D printed and there has recently been a wave of some realized via LEGO.

Today’s puzzle is Gentle Interlock designed by Junichi Yananose from Pluredro.  Junichi has many more buyers than puzzles, resulting in his puzzles selling out in minutes or even seconds when they are released.  And he rarely has a second release of a puzzle since he is always working on the next design.  So he does his best at discouraging people from buying his puzzles.  In the case of Gentle Interlock, although there were prototypes of level 10 and 11, Junichi opted for the design with the lowest level - 6.  In his defense, he opted for this design stating that it had better playability.  As brilliant as all Junichi’s designs are, I took a gentle pass.

Fast forward to this year’s New York Puzzle Party (More PPing in the Big Apple – NYPP 2025)  where someone brought a copy of Gentle Interlock that gently tickled my brain and reminded me of this puzzle and how much I like burrs.  With that thought worming it’s way through my wormy mind, I eventually got around to pulling one from the replicator.

Gentle Interlock initially looks like a typical 6 piece burr but on closer inspection one end of each piece appears to be twice as large as expected.  This pushes the pieces away from the center thus providing more space to add bits where the sun don’t shine.  It also adds a nice bit of confusion since it orients what you may consider the center-facing side of the piece towards the side or even away from the center.

Since this puzzle was extracted from the replicator, it arrived unassembled.  Perfect!  The assembly is not trivial and it took me some time to work out where all the pieces needed to go and then how to assemble them.  Junichi certainly hit the playability goal he was aiming for.  However, I’m left wondering what the higher level designs would have been like.

Gentle Interlock was a fun puzzle and maybe one day, it will end up in a free bundle on MPD.

Amazingly Non-Burrish – Gravitational Burr

Yes, yes, it looks like a burr but when you get into it you’ll start to realize the gravity of the situation – it’s amazingly non-burrish.  So if burrs aren’t your thing, don’t worry.  If you can pull the contents out of the belly of a crocodile, you can solve this one as well.

Gravitational Burr was designed by Junichi Yananose (Juno) from Pluredro and made using American Black Walnut.  It consists of 6 standard burr pieces that look like they have been made from wood infested by boring insects.  However, the boring traces were intentionally added to provide a path for a ball bearing to meander along a dynamically changing path.  

Since it arrives assembled, the first task is to take it apart.  Of course, all those boring paths are hidden and you have to blindly embark on this journey.  About halfway through, you can get a good look at the amazing interior and start to deduce what needs to occur to get to the finish line.  Unfortunately as I age, I find that my deducing is reducing.  But deducing I went as I tried to hold a dynamically rotating piston-driven image in my head.  Needless to say, there was a lot of backing up and restarting involved.  And lots of Oh, I’m back here again moments.

When I finally navigated the path to the end, I was super impressed that the ball bearing didn’t just come dropping out.  Juno designed it so that the ball bearing would be secure when it came to disassembling the pieces.  And this attention to detail is what makes Pluredro’s puzzles so special.

Once apart, you can get a good look at all the pieces to see exactly how they interact with each other.  You will also notice a compartment that could be used to store something inside. This internal space can be used to justify it as a puzzle box for those desperate collectors that only purchase puzzle boxes.  Or maybe as a poke to those that collect burrs and refuse to buy puzzle boxes.  I suspect that some people received it with a loaf of bread inside.  The puzzle description indicates that you can store the ball bearing in this cavity to inactivate the maze and reduce the number of moves from 56 to 2.  However, I wouldn’t recommend it since there is nothing to secure it and it will eventually fall out and roll into some dark and mysterious place where things go to never return.

Since this really isn’t a burr challenge, it’s not difficult to get the pieces back into the starting position for the return trip.  To get you started, 2 pieces have matching magnets to provide a nice tactile feel to the puzzle and the other pieces just seem to fall into place to provide the maze required for the ball bearing.  You just need to determine the order to add the pieces, which isn’t difficult.

Surprisingly, I found the reassembly more difficult than the disassembly.  Knowing and doing are really two different things.  Event though I had a mental image of the entire dynamic map, the blind traversal of the path took several tries before I had it back to the beginning.  Again, I was impressed with the design and how it avoided being reset at the mid-point.